Trevor Cahill was drafted by the Oakland Athletics in the second round of the 2006 draft, out of high school in Vista, California. He had strong academics and a Dartmouth scholarship, leading to signability concerns, but Oakland got the job done and he signed in time to make four starts in the Arizona Rookie League, pitching just nine innings due to a strained rotator cuff, but posting an 11/7 K/BB ratio.
In 2007 he went 11-4, 2.73 with a 117/40 K/BB in 105 innings for Kane County in the Midwest League, with just 85 hits allowed, three homers given up, and a 1.73 GO/AO ratio. In 2008 so far, he's 5-4, 2.78 with a 103/31 K/BB in 87.1 innings for Stockton in the California League, with 52 hits and three homers allowed, with a 2.19 GO/AO ratio.
Obviously these are excellent numbers...strong ground ball tendency, excellent K/IP and H/IP marks, few homers allowed, non-horrible walk rate. But Cahill generates different opinions from scouts and observers. Although his velocity has picked up some (hitting 93 MPH at times this year), he still works mostly in the 89-92 range, not plus velocity, granted his fastball has strong sinking action. His curveball and changeup are both fine offerings, and his intelligence and confidence are big assets.
However, the lack of a big-time massive plus velocity heater causes some to project him as more of a Jeff Suppan control, inning-eating type than a true future ace. Others point out that not every great pitcher has great velocity, and Cahill's intelligence and guile are huge assets. The sabermetric case points to the combination of strikeouts and ground balls as a big positive.
Personally I am on the pro-Cahill side, though I want to see exactly what happens to him when he reaches Double-A. I gave him a strong grade B in the book this year, and have no problems raising that to Grade B+ given what he's done in the Cal League. I would like to see his walk rate come down a little, and I also have some concerns about whether that rotator cuff issue will recur at some point. But overall there is a lot more to like here than there is to dislike.