Wade Davis' second big league start, which came in a 9-1 loss Saturday against the Red Sox, didn't go as smoothly as the first, but in his two-plus innings of work he still showed why he's one of the top pitching prospects in the game and why the Rays felt they could trade Scott Kazmir for more prospect depth. Davis is a big, physical kid, listed at 6-foot-5, 220 pounds, with some room left to fill out, giving him plenty of workhorse potential. His arm works well, he gets on top of the ball from a three-quarters slot, and he repeated his delivery. He showed four pitches on Tuesday -- two- and four-seam fastballs, a curve and a show-me slider. The four-seamer was 92-95 mph with good downhill plane but lacked lateral movement, while the two-seamer was 90-92 with sharp tailing action down and away from left-handed hitters. His curveball is an out pitch right now, 79-82 mph with great depth and two-plane action, and he showed tremendous confidence in it, doubling it up, throwing it to left-handers and (a little late) flipping one in for a first-pitch strike in his final inning. The slider was his worst pitch and he didn't throw many -- 86-87 mph with long break that puts it out of the strike zone; he also falls off harder when trying to throw the slider away to right-handed hitters. His command, despite the lousy results, was fine, and he showed he could spot his four-seamer to the corners in the first two innings. He worked quickly but takes a while to get the ball to the plate with men on, running about 1.7 to 1.8 seconds from when he starts his delivery from the stretch to when the catcher receives the ball, which will make stealing bases off him a breeze. Davis' undoing was largely one of approach. The second time through the order, Boston's hitters began sitting on fastballs, and Davis complied by continuing to throw a lot of them, especially on the first pitch. He can throw his curveball for strikes, but went to the four-seamer 1-0 to Alex Gonzalez, 0-0 to David Ortiz, 0-0 to Victor Martinez, and 2-1 to Kevin Youkilis, giving up hits to all four. I could understand trying to blow the ball by Ortiz, who has lost bat speed, but both he and Gonzalez were cheating on the fastball and were easy prey if Davis had flipped a curveball in there. He gave up one hit on a curveball in his entire outing, a hanger that sat up and in to Dustin Pedroia, who likes the ball there and punched a soft single to left. Establishing the fastball the first time through the order is a good idea when you have plus velocity, but in the big leagues, hitters will make adjustments the second time they see you, and you need to be willing and able to change your approach. If he shows he can do that, Davis has No. 1 starter potential.It's also worth noting that Dioner Navarro did Davis no favors behind the plate. Navarro, never a great receiver, was awful on Saturday, pulling several strikes out of the zone and bobbling two pitches with runners going. "Framing" pitches is a tough skill to measure, and its importance is probably overstated in the traditional view of the game, but on Saturday, Navarro's failure to frame pitches definitely cost Davis two strikes and may have cost him as many as five.