While some of you owners are plugging away to finish off your title run this week, many of you are already looking ahead to next season. Whether you're getting a head start on your competition or planning your title defense, it's important to learn a little about those prospects who could make a splash in 2012.While most prospect lists rank players for their value over the long haul, this one has a narrower frame of reference. This set of rankings projects prospect value strictly on potential fantasy contributions for the 2012 season, not 2013 or any seasons beyond that. Thus, you won't find potential down-the-road stars such as Manny Machado here. There's a difference between the best prospects overall and the best prospects for the six-month timeframe that is the 2012 season. It's why players such as Ben Revere (32 steals), Jordan Walden (31 saves), Cory Luebke (3.27 ERA, 1.07 WHIP, 9.9 strikeouts per nine innings, No. 44-ranked starting pitcher on our Player Rater) and J.P. Arencibia (23 homers), all made last year's "Top 20 prospects for 2011" over players with more long-term upside.As such, don't get too hung up on the particular rankings at this stage; focus instead on the players themselves. Things will change based on offseason roster moves (trades, free-agent signings) as major league teams reshape their rosters for next season. New opportunities will open up for some players and close for others. This is just a snapshot based on how things look right now, well before Opening Day 2012. Projected playing time is obviously the key for fantasy purposes, and who gets a shot in 2012 depends on a variety of factors, such as team needs, injuries, performance or sometimes just being in the right place at the right time. For example, Brett Lawrie became a bigger presence on our 2011 radar screen after his offseason trade from Milwaukee to Toronto.To have some kind of parameter as to who is eligible to be on this list, I choose to use Major League Baseball's rookie-eligibility standards, which means a player has not: A) exceeded 130 at-bats or 50 innings pitched in the major leagues, or B) accumulated more than 45 days on the active roster of a major league club or clubs during the period of the 25-player limit (excluding time in the military service and time on the disabled list). In other words, he needs to be rookie-eligible in 2012 to appear here.Also worth noting: There are a few players below who are still under the at-bat or service-time threshold for rookie status as we enter the final games of the season but might cross it (and no longer be rookie-eligible) by the end of the month. Rather than playing a guessing game about playing time, I have chosen to include them; I felt that was most appropriate. I have excluded players who were no longer rookie-eligible as of the publish date, such as Dee Gordon, Paul Goldschmidt and Brandon Belt, among others. I have also excluded players who spent most, if not all, the season in the minors but have long since used up their eligibility as well, such as Dayan Viciedo and Lorenzo Cain. If you have questions, fire away in the conversation area.With that, let's get to the Top 20 prospects for 2012:1. Matt Moore, SP, Rays: It just so happens that the best pitching prospect in baseball is ready to make an impact at the big league level very soon, and I expect the Rays to be active in the trade market this offseason, knowing they have pitchers such as Moore and Alex Cobb ready to step into their rotation full time. The left-handed Moore can dial up his fastball into the high-90s with an easy delivery, adding and subtracting velocity as needed. He has a true out pitch breaking ball -- some scouts classify it as more of a slider, though Moore throws it more like a curve and alternates between calling it that and just a "breaking ball" -- and the development of his circle changeup this season gives him three legitimate weapons at the big league level. The progression in his control the past three seasons in the minors while maintaining a strikeout rate of better than 12 batters per nine innings is equally encouraging. Even if he doesn't start the season in the Rays' rotation, he'll be in there before long, and he projects to be a true big league ace. I profiled Moore, with more details, after his impressive performance at this year's Futures Game.2. Mike Trout, OF, Angels: Despite some flashes here and there, Trout's numbers in his first stint in the majors haven't been overwhelming. Then again, he's still only 20 years old. The Angels have the same cast of characters in their outfield and DH spots under contract for next season, but I don't expect that to be an issue in terms of Trout's playing time. A complete player with the ability to contribute across the board, Trout's 80 speed on the 20-to-80 scouting scale can help him provide value even while his bat continues to adjust to big league pitching, and his defense will help keep his name in the lineup. His short swing and bat speed will allow him to post both high batting averages and 20-homer campaigns down the road, and we should see some of the seeds of that next season. I profiled Trout in more detail following his appearance in the Texas League all-star game. He's one of those who might lose his rookie eligibility in the final week of the season, but he definitely should be considered an emerging prospect.3. Brett Jackson, OF, Cubs: This 23-year-old has a strong shot to open next season as the Cubs' starting center fielder after a 20-homer, 20-steal campaign (with a .379 on-base percentage) across Double- and Triple-A this season. Jackson's line-drive stroke can hit the ball to all fields, his bat speed gives him good batting-average potential and his good batting eye should help keep his OBP (and thus his steals chances) high. He's not a true burner, but he's an above-average baserunner and defender in center. He might have some issues making contact at times -- he has a tendency to pull off the ball on the outer half of the plate -- but it will be acceptable given the rest of the package, and his potential for a lot of at-bats next year means fantasy owners should watch him closely.4. Jesus Montero, C, Yankees: Montero's power bat was dormant for much of the first half of the season amid reports he was growing frustrated with being stuck at Triple-A for a second straight year, but his stick came alive in the second half. He posted a .558 slugging percentage and 11 homers in his final 147 at-bats at Triple-A by reducing the uppercut tendency that had crept into his batting stroke. That earned him a promotion to the majors, where he has shown enough that he's now a good bet to make the club's postseason roster.In some leagues, Montero won't qualify as a catcher to start next season, and the concerns about his defense behind the plate have been well-documented and don't help his case for regular playing time if the Yankees fill their DH slot with a free-agent slugger. That said, Montero's power upside from a backstop, with the ability to post a solid batting average to go with it, make him a good fantasy asset.5. Yonder Alonso, 1B/OF, Reds: Alonso can hit at the big league level, but as long as Joey Votto is around, he'll be playing out of position for the Reds. If you've gotten to watch him, you've seen the struggles he has had in left field. Presuming he is not dealt this offseason, the plan is for Alonso to shed some weight, work on his quickness and mobility and try to make a go of it as a starting left fielder next year. Scouts remain skeptical, but the Reds have shown a willingness to live with poor defense from their left fielders before (see: Jonny Gomes) as long as the player produces offensively. I wrote about the offensive potential of Alonso, the seventh overall pick in the 2008 draft, in more detail in July.6. Julio Teheran, SP, Braves: Teheran hasn't been impressive in his first exposure at the big league level this season, but he doesn't even turn 21 until January, and I expect a big step forward next season. The raw stuff is there; the right-hander just needs more consistency with his fastball location and the spin on his curve and to trust his ability more. The bottom line is Teheran has the ability to pitch at the front of a big league rotation with two plus pitches and a third that will be at least average. I'm not concerned about his lack of swings and misses in his limited big league stint because the raw ability is there to generate those. They will come as he improves his consistency.I'd be remiss if I didn't mention two other highly touted Braves pitching prospects: Randall Delgado and Arodys Vizcaino. With a reasonably healthy staff next season, the Braves won't have room for all of them, and Teheran has the biggest ceiling. But all three players are worth tracking over the course of next season.7. Shelby Miller, SP, Cardinals: Miller might not open the 2012 season in the Cardinals rotation, but he's likely to spend a good amount of time in it and finish the season there. He has the arm to generate easy high-90s velocity with a live fastball and a plus breaking ball, and he's developing a feel for his changeup. He's aggressive in attacking hitters and just needs to keep refining his overall control and command, and gain experience. He's probably ready to start racking up big league outs as soon as next year. I profiled Miller in more detail here.It's worth adding that Miller was suspended for a week in August for what was reportedly an alcohol-related incident. He also experienced some soreness in his biceps this season. But I don't expect either to be an issue going forward.8. Jacob Turner, SP, Tigers: Turner is another talented young right-handed pitcher -- he'll still be just 20 on Opening Day next season -- who likely will show some growth and establish himself at the big league level next season. He definitely has lived up to his ninth-overall-pick status (in the 2009 draft) so far. He doesn't blow you away with velocity (though he can dial it up when he needs to), focusing instead on his two-seamer, which has late sink, to set up both a plus curveball and a changeup he can throw for a strike. He's very polished for his age; he just needs more innings and experience to finish off the package. Still, there can be some fantasy usefulness next season while we wait for that. My in-depth profile of Turner is available here.9. Drew Pomeranz, SP, Rockies: Pomeranz's fastball and "hammer" curve already rate as plus pitches; he'll go as far as his fastball command and the progression of his circle change will take him next season, which could be pretty far. He has a good shot to make the Rockies' rotation to begin the 2012 season. I profiled Pomeranz in detail shortly after he came over to the Rockies in the Ubaldo Jimenez trade.While mentioning Pomeranz, I should also mention the other pitcher he was traded with, Alex White, who I profiled earlier this season. Technically, White is still rookie-eligible because of all of the time he spent on the disabled list due to a finger issue that isn't common in baseball. I like White a good deal and think he can be a solid No. 3 or 4 starter in the big leagues, but he hasn't looked quite the same since coming back from the finger injury. He's just not getting the sink on his fastball or the bite on his secondary stuff. I want to at least see him again in the spring before deciding how aggressively I want to project him next season.10. Jarrod Parker, SP, Diamondbacks: Parker hit some predictable bumps in the road earlier this season in his return from Tommy John surgery, but he got stronger and more consistent with his command as the season went along. His mid-90s velocity returned, and he started pitching to both sides of the plate better as he found his location again. His slider projects as a plus pitch, and he maintains his arm speed well on his changeup. He'll also mix in a curveball that flashes as an average pitch. He can give batters a lot of different looks with a solid delivery that gives him command potential. Parker will be ready to enter the D-backs rotation early next year, and his strikeout ability and ground ball profile can help him have success right away.While I'm discussing Parker, I should also discuss organization mate and 2011 first-round pick Trevor Bauer, who is clearly on the fast track to a spot in the big league rotation. In fact, I nearly gave Bauer a separate entry in the Top 20. Both should be a part of the D-backs rotation by the end of 2012, but I think Parker is the better play for next year.11. Anthony Rizzo, 1B, Padres: Rizzo dominated Triple-A pitching this year in the hitters haven that is the Pacific Coast League, but his flaws were exposed in his short big league tenure. I expect him to do a better job closing some of those holes next season. I mentioned earlier this year after I saw him at Triple-A that I was a bit concerned that his swing wasn't always consistent, and that he could get a little too long with it. I feared big league hurlers could take advantage of him on the inner half, which they did. He also still needs to get better against southpaws (24 of his 26 Triple-A homers this season came off righties). However, the tools are there for him to be a run-producer, and I think he can take a step forward next year.12. Devin Mesoraco, C, Reds: Mesoraco is an offensive threat at catcher, and he's not in danger of being moved from the position. He can hit 20-plus homers in full-time play while making contact and handling the strike zone well because he gets his hands to the ball quick, and he's likely to get the lion's share of playing time in Cincy next season, although Dusty Baker has leaned toward having more of a timeshare with his catchers in the past. Feel free to check out my more in-depth look at Mesoraco, which I wrote in mid-June.13. Leonys Martin, OF, Rangers: The Rangers might want to give the 23-year-old Cuban defector the first shot at their center field job next season, or at least a very long look there at some point. There's a bit of skepticism about his swing -- Martin was out in front too often at Triple-A and wasn't hitting for authority due to a lack of consistency in his stroke -- but that's likely correctable, and he can cover up some of his flaws with his good bat speed. He helps his playing-time cause by being a plus defender, including a 60 throwing arm on the 20-to-80 scouting scale. He also has above-average raw speed; he just needs some refinements in his base-stealing technique to become a legit steals guy. He has the chance to hit for batting average with stolen base ability as early as next season.14. Nathan Eovaldi, SP, Dodgers: Eovaldi has shown enough in his big league stint this season to project some success from him next year as he cheaply fills one of the Dodgers' rotation holes. He'll sit in the mid-90s with his fastball and touch as high as 98 when he reaches back for something extra, and his slider is a quality pitch he can locate, with the bite to get swings and misses. He has the capability to throw more strikes than he has in his short stint in the big leagues, and he's going to need to throw his changeup more to help keep more hitters off balance, but he could be quietly effective next season.15. Henderson Alvarez, SP, Blue Jays: Alvarez likely will go over the innings threshold to be considered a rookie in 2012, but I felt I should include him here since he's still a relatively unknown commodity. He'll sit in the 93 mph range with his fastball with some tail or cut on it, and can dial it up to 97 as needed. His changeup gets hitters out in front with its big sink, giving him a solid two-pitch base to work off. His slider is still in development, as its movement is inconsistent, but he can at least throw it for strikes, and it projects to be a big league average pitch. He also has a curve that he has thrown in the minors but hasn't busted out in the big leagues yet because it lags behind the other pitches. Kyle Drabek was a touted rookie who flamed out spectacularly when given a full-time rotation gig this season. I don't expect that pattern to repeat with Alvarez.16. Ryan Lavarnway, C, Red Sox: This is likely the last year we see Jason Varitek in a Red Sox uniform (as a player anyway), so there's a good chance Lavarnway and his power potential will get at least a share of the catching job at Fenway next year. However, his below-average defense could limit him to only occasional starts behind the plate. He lacks agility as a catcher, and his arm accuracy is his best asset. Still, his power can play at the big league level. I went into more detail about Lavarnway's offensive upside and defensive concerns in an August blog post.For now, I'd take the chance on Lavarnway for 2012 over other catchers such as the Royals' Salvador Perez (who can hit for batting average, but not for power yet) and the Rockies' Wilin Rosario (whose power is his main asset, but plate discipline is an issue).17. Joe Wieland, SP, Padres: I'm playing a hunch here by including Wieland. I'm a big fan of his four-pitch mix (with control), and I think he'll step up and grab a spot in the Padres' rotation sooner rather than later. His home park and projected defense behind him can only help him. Pegged as a command righty entering the pros, he's showing he has the stuff to be much more than that. For 2012, I'll take Wieland over other top pitchers in the Padres' system, such as Casey Kelly or Robbie Erlin.18. Wily Peralta, SP, Brewers: This 22-year-old has shown he's capable of stepping into the Brew Crew rotation next season by fanning 157 batters in 150 2/3 minor league innings this season, not missing a beat when he was promoted to Triple-A late in the year. The right-hander attacks the strike zone with 92-95 mph fastballs that appear to get on the batter quickly, and his sinking low-80s changeup is an effective weapon against lefties. His slider showed sharper bite and was more consistent this season, and he trusts all three offerings. He has been a little under the radar as a prospect, but he's a solid three-pitch future starter with strikeout ability.19. Brad Peacock, SP, Nationals: Even given all of his success in the minors this season, I still have some skepticism about Peacock's ability to stick as a consistent, successful big league starter as opposed to just a good bullpen arm. I went into greater detail about those concerns in a blog post earlier this season. Essentially, Peacock's straight changeup is still a work in progress, and he must show better overall command and control if he's going to be essentially a two-pitch starter. He also had some issues with control after leaving Double-A. I'm giving him the benefit of the doubt for now, especially since he has shown he can miss some bats.Peacock's teammate, control-artist Tom Milone, is also a name to watch, although his lack of a plus offering and high-80s fastball limit his ceiling to that of a back-end starter at best.20. Zack Cozart, SS, Reds: Cozart is expected to return from elbow and ankle surgeries to assume the Reds' starting shortstop job in 2012. He can hit for batting average and has the potential to reach double-digit output in both homers and steals in full-time play. That combination could make him a useful piece at a shortstop position that had depth issues this season. He's not going to be the kind of player that wins you titles, but he can certainly fill a role on a fantasy team as a capable producer with a starting job.And where's Bryce Harper? Well, I was tempted to put Harper here as a sort of a "symbolic" No. 20, but I just couldn't. In doing so, I'll address the inevitable questions about him. I've said from the very start of his pro career that I saw Harper's timeframe as an arrival in late-August/September 2012 and ready to make an impact as a starter the year after that. I haven't altered that assessment. Could Harper light up the Arizona Fall League, spring training then Double-A early next year to get himself more than a cup of coffee in 2012? Sure, that's definitely possible, but I think 2013 is more likely.Sept. 21 update: It was pointed out in the conversation area below that Indians second baseman Jason Kipnis still has a chance to remain rookie-eligible because of the time he spent on the disabled list in 2011. I had inadvertently lumped him in with players such as Brett Lawrie as no longer eligible for rookie status. So for those wondering where Kipnis would fit among the rest of the names above, I would rank him third on this list.