Zack Wheeler, RHP: The Giants drafted Wheeler in the first round in 2009, from high school in Dallas, Georgia. He was the sixth-overall pick in the draft. The 21-year-old right-hander posted a 3.99 ERA with a 70/38 K/BB in 59 innings last year for Augusta in the Southern League. The Giants have stretched his pitch counts out more this year, but the per-inning results are very similar: a 3.99 ERA in 88 innings for High-A San Jose in the California League, with a 98/47 K/BB, 1.35 GO/AO, and 74 hits allowed. Wheeler has a low-to-mid-90s fastball. His changeup has improved but is still spotty, and reports vary on the quality of his breaking ball. His command needs work as well, but his K/IP ratios point to strong potential going forward. I had him rated as a strong Grade B prospect pre-season and will stick with that for now. He has the potential to be excellent, but still needs refinement.
For a detailed scouting report with particular concentration on Wheeler's breaking ball, check out this post from Alex Nelson at Amazin' Avenue.