In 2010, Duda had a breakout minor league campaign, cranking out 65 extra-base hits between Double-A and Triple-A and hitting .304 with 23 homers in 425 at-bats. He hit just .202 in 29 big league contests but did have 10 more extra-base knocks, including four homers.The key for Duda was getting more of his whole body into his swing. For years he didn't incorporate his lower half into his stroke too well or get good leverage. Last year he made some mechanical adjustments to give him more of a base to hit from. He also altered his approach slightly. Plate discipline isn't just about taking walks but knowing when to attack stuff you can turn on, and Duda became more of a pull hitter who looked for stuff on the inner half he could yank down the right-field line. Some hitters are better suited to be pull hitters rather than hitting to all fields, and I think Duda fits that description, although he can still go the other way to the gap. His pitch recognition helps compensate for a lack of great bat speed, and he doesn't completely sell out his swing to hit for power.Duda has hit just four homers in 173 at-bats this season, but there's more juice there. He showed it again in the minors this season, despite battling some back problems in May. He must watch his toe tap and get his foot down in time to make sure that lower half remains a big part of his swing. He fell back into an old rut and struggled with that when he was first promoted, causing a homer drought. But I saw him this weekend, and didn't see any issues there.Duda is a below-average defender no matter where you put him, so his bat, and more specifically his power, is going to have to carry him. He still has to show he can hit southpaws with authority, something that was also an issue in the minors and might limit his ceiling. But Duda has the potential to hit right-handed pitching quite well, and that could make him useful in shallow NL-only leagues and maybe even deeper mixed ones while he's getting regular at-bats. There's a little more potential here than you might realize, at least in the short term.

Other notes

• It has been a bit of a mixed bag for the Diamondbacks' Paul Goldschmidt at the big league level thus far. I profiled Goldschmidt in May, when his numbers first began to stand out in Double-A, and addressed some of the questions about how well his swing would work at the big league level.He has had some good moments, such as the game-tying pinch-hit homer with two out in the ninth inning against the Astros last Thursday and a three-hit contest with two key doubles and an RBI in a win against the Mets on Sunday. However, he has struck out in 18 of his 41 at-bats. That strikeout percentage isn't quite as bad as it might seem, though, because the 23-year-old first baseman has put together some good at-bats that have ended in strikeouts. In fact, he has seen an average of 4.30 pitches per plate appearance thus far, which would be the highest mark in the National League if he were to qualify (Jayson Werth leads qualified batters with a 4.28 mark)."Obviously, coming in to the big leagues, I knew there were going to be some adjustments," Goldschmidt told me Sunday. "Pitchers aren't going to make as many mistakes." Mistakes were something he feasted on in the minor leagues.Goldschmidt credits his changed approach for the monster numbers he put up in Double-A this season, yet says the work is not done. "I think it was just being consistent with my approach at the plate and being patient when it was time to be patient, and being aggressive when it was time to be aggressive," Goldschmidt said. "It was my biggest improvement, but it's also the thing I still need to work on the most."As is usually the case with young hitters, Goldschmidt is trying to find that balance between patience and aggressiveness. He's working on being "selectively aggressive" at the big league level, attacking mistakes and drivable pitches early in the count. At times, it appears his timing has been just a bit off, and he hasn't gotten the barrel of the bat on some pitches that he probably should have. Still, a .463 slugging percentage from a 23-year-old in his first 12 big league games is a good start, and it should help him continue to get a lion's share of the playing time at first base, even with Lyle Overbay now in the fold.I still think some of the concerns I mentioned earlier this season about Goldschmidt are valid. I will point out that scouts also had some of those same concerns about Mark Trumbo and his swing entering this season, and while Trumbo's OBP currently sits below .300 (it's at .294), he has handled right-handed pitching better than expected and is on pace for 29 homers.Look past Goldschmidt's early strikeout total and you'll see a player you should at least take a chance on in mixed leagues in hopes of catching lightning in a bottle, especially given the decreased lack of depth at the corner infield slot this season. I'd take him over Duda right now if I had to choose at first base, although you might value Duda's added position eligibility (he also qualifies in the outfield).• Jason Heyward owners, especially those in keeper and dynasty leagues, have to be feeling a little nervous about their guy right about now. Where is that superstar outfielder who was supposed to emerge? His swing is messed up, he has been unproductive and he continues to lose playing time to Jose Constanza in the short term.While I don't think I can offer much solace to those hoping for Heyward contributions this season (although it's certainly possible he could turn things around in the next month and a half), I think I can ease the concerns of those of you who own him in long-term formats.In my mind, a lot of Heyward's issues this season can be traced back to his shoulder problems; his shoulder reportedly has been an issue for much of the season. When he went on the disabled list in May, I recommended picking him up on the cheap, if he was available. In hindsight, it appears I underestimated just how much that shoulder was affecting him and would continue to do so. By the way, this Stephania Bell blog about Heyward's shoulder injury and how it turned into a bit of a "thing" is a must-read to refresh your memory.Now, Heyward did go on record last week as saying his shoulder was not the cause of his recent struggles, but I'm not certain that's accurate. While he might not be feeling any pain (or perhaps is reluctant to make any excuses publicly), his swing hasn't been right for quite some time. Shoulder injuries can sap power and mess up swing mechanics as players compensate for discomfort or pain by changing their swing, even if they don't realize they're doing it.Heyward has, at times, had trouble getting the bat started and has appeared to have problems getting through the ball, things that I think can be traced to his shoulder problems. The result: He's having trouble driving the ball, which is not a good thing for a batter who had a moderate ground ball profile to begin with. Just because Heyward hasn't had to miss any more time due to the problem doesn't mean it's 100 percent healed or isn't an issue in other ways. The hope is an offseason of rest allows the 22-year-old to come back strong in 2012, not only with renewed health but a renewed swing that is more like the one we saw in 2010.