Keep in mind that this is not a traditional top prospect list because it focuses entirely on 2012 contributions. I rank guys according to advanced metrics which, for position players, include batting runs above average, positional adjustment, defense, and a replacement level calculation that scales the total to "Wins Above Replacement" (though the concept of replacement level doesn't really apply to minor leaguers). I use a standard "runs allowed based" WAR formula for pitchers.
1) Kaleb Cowart, 20, 3B - 4.5 WAR, +14 bat, +8 glove. .276/.358/.452 with 16 HR and 14 SB
For the third year in a row, the system's top prospect is also its top performer. Always nice when there's a little order to the universe.
Cowart entered 2012 with questions about his glove and bat. I never understood why folks were down on his glove - he's a fine athlete with good body control, he looked great in the field when I saw him in 2011, and everyone makes errors on Pioneer League dirt - but I was worried about the bat, specifically his contact skills. Baseball has generally been unkind to 19-year-olds who strike out in a quarter of their rookie ball plate appearances. My line was, "Cowart's K's aren't likely to just go away, and that's going to be prohibitive unless the secondary skills come along quickly."
The secondary skills came on fast. First, there was the .186 isolated power and nine HR's he popped off in the first few months of 2012 while playing in the pitching friendly Midwest League (especially true in the cold spring). Then, following a promotion to the Cal League, he doubled his walk rate to nearly 15%. He ran out of gas in the season's final month and limped through the Arizona Fall League with a .548 OPS, so he'll need to get stronger to hold up under the rigors of a full season. I don't think he's entirely left the K-monster behind him -- I always think of former Dodger prospect and now Arizona replacement-level-type Josh Bell, who is an eerily similar player and has fanned in a third of his big league PA's -- but he's improving rapidly and his physicality, athleticism and growing skill with his left-handed swing all engender confidence.
Cowart's made most top prospect lists so far, topping out at 23rd on Keith Law's list. Will Lingo ranks him 47th (Baseball Prospect Handbook). John Sickels rated him the 35th best hitting prospect, so he would fit on the back half of his top 100 of he combined lists (Sickels' prospect book). He's 67th on Jonathan Mayo's MLB list. Overall, his median ranking is 58th, which seems to me an accurate valuation of his present skills and risks. Maintaining his production against AA competition would vault him up the list, but I think it's fair to acknowledge the very real possibility that advanced pitching picks him apart.
What I'm most interested in seeing is how Cowart's career progresses in comparison to Nick Castellanos' (median rank of 19th) and Mike Olt's (median rank of 23rd), two third basemen whom the Halos passed on in favor of Cowart in the 2010 draft. I'd take Cowart over Castellanos today - Cowart has a broader skill set, and I don't think there's any guarantee that Castellanos keeps hitting the way he did in A-Ball, let alone develops any real power - but Mike Olt is a really compelling package. Like Cowart, his challenge will be keeping the K's in check. Who does that better, the supplemental first round college pick, or the high upside high school pick, will provide a nice little case study for those of us whose formative years took place during Bane's tenure as the Angels' scouting director.
Below is a full length scouting video on Cowart, courtesy of the Bullpen Banter folks. Skip ahead to 3:29 if you want to see an in-game, opposite field double. Or, check out good footage of Cowart's lone Scottsdale HR here. Or another double with the Quakes, here.
The scouting report on Cowart finally caught up with his numbers this offseason: from the left side, Cowart has more patience and power but a tougher time with contact (20% k-rate, 271/.361/.473); and from the right side he's more of a line drive/groundball hitter who depends on batting average (14% k-rate, .297/.360/.414). Previously, scouts had always preferred the fluidity of his right-handed cut, even if the production was better from the left side. There's now some quibbling over the "loop" in Cowart's lefty swing (BA Prospect Handbook), the complaint being that it causes him to pop up too much, but the numbers don't support that at all: his 3% infield fly rate was well below average. Every time I saw him hit in 2012, dropping the bat head either helped him to stay inside the ball and go to the opposite field or to pull for power. The only quibble I'll have is if he swings and misses too much in 2013.
Here's MLB's video, though you might now have to sit through a Geiko add before the video: