Carlos Villanueva was signed by the Giants as an undrafted free agent out of the Dominican Republic in 2002. He made his pro debut with the AZL Giants that year at age 18, posting an 0.59 ERA and a 23/3 K/BB ratio in 30.1 innings. His command was obviously outstanding, but his mediocre stuff kept him off most prospect lists, including mine, pending higher level data. I would have given him a Grade C.
Villanueva returned to the Arizona Rookie League in 2003 and became a starter, going 3-6, 3.97 with a 67/13 K/BB in 59 innings with 64 hits allowed. Again the strong K/BB stood out, but as a league-repeater he needed to prove out at higher levels to move past Grade C.
The Giants traded him to the Brewers in March, 2004. Milwaukee sent him to Beloit in the Midwest League where he had a solid season in the rotation, making 21 starts with a 3.77 ERA and a 113/30 K/BB in 115 innings. HIs only negative stat was 20 homers allowed. By this time he'd boosted his velocity a bit into the 88-92 range. I gave him a Grade C+ in the 2005 book, pointing him out as a sleeper if he could get the home run tendency under control.
The Brewers sent him to the Florida State League to begin 2005. He did great, posting a 2.32 ERA in 21 starts with a 124/32 K/BB in 112 innings. A late promotion to Double-A resulted in a 7.40 ERA in four starts with a 14/9 K/BB in 21 innings with 21 hits allowed. His fastball was back to the 87-88 range at the end of the year, and scouts indicated that Double-A hitters weren't as easily fooled by his arsenal, granted the sample was small. I lowered him to Grade C in the '06 book, noting however that he deserved more chances and that he still had some sleeper potential.
Villanueva opened 2006 in Double-A and pitched well; he continued pitching well in Triple-A, then ended the season with 53.2 strong innings for the Brewers. Last year he pitched 114 innings for Milwaukee with a 3.94 ERA. In 168 career innings entering 2008, Villanueva has a 138/64 K/BB with 144 hits allowed and a 3.86 ERA.
What does the future hold?
PECOTA seems to hate him, giving him a collapse rate of 60% entering 2008. His comparables list includes scary comps like Todd Van Poppel and Ken Cloude, but also a few more successful guys like Mudcat Grant and Moe Drabowsky. Although in the rotation right now, my personal belief is that he is best utilized in the long relief/spot starter role, and that as a full-time starter he would be more likely to get overexposed and fail.
Villanueva is a Grade C/C+ prospect made good, and I tend to root for guys like this. If he stays healthy I think he will have a mixture of good and bad seasons, the kind of guy who will post a 6.00 ERA in a bad year, drift to another team, then turn things around quickly and post a 3.00 mark in a limited role, before being overexposed and struggling again. In the end I think Villanueva balances out as an average major league pitcher overall, but that's not an insult, and he gives hope to every guy in Double-A who has average stuff and is looking for a break.