One of the more interesting (and harder to evaluate) pitchers going into the 2007 baseball season is Hong-chih Kuo. His minor league record suggested that he'd be a dominant (9+ K/9) reliever in the majors, but would struggle with his control. Typically a pitcher like that is going to be only marginally effective as a starter, where they won't strike out as many batters, but will still struggle with control. If you look at his overall statistics for the 2006 season (his first full season in the majors) they look very much the way you'd expect his stats as a reliever to look: 59.2 innings pitched, 71 strikeouts, 33 walks.
But things get interesting when you look at his splits between starting and relieving. In 5 September starts, he struck out 35 and walked only 7 batters, in 29.1 innings. That's an amazing performance. It also means that as a reliever last year he struck out 36 and walked 26 in 30.1 innings. That's not so amazing. In fact, that's remarkably similar to Daniel Cabrera numbers, except that Kuo did it against the easier competition in the NL. Kuo has also been quoted as saying that he's more comfortable as a starter than as a reliever. So should we assume that he's a great sleeper pick if he's in the LA rotation, but that he will fail in a relief role? I don't think so. Only two of his relief appearances were after he returned in September and he struck out 7 batters and walked 2, in 3 innings pitched. So I think he would have excelled in either role late in the year. Its VERY unusual for a pitcher to put up numbers that are so much better as a starter than as a reliever, so I have to assume that something was wrong earlier in the year...either he had a minor injury or there was a problem with his pitching mechanics that got worked out. I'm confident he can excel in either role, and that his rate stats (K/9 and K/BB) will be better as a reliever than as a starter. That said, I think until he does it again, his incredible September performance has to be viewed more as a display of his full potential than as an indication of his current skill level. Expect numbers similar to his overall stats last year, but there's potential for a lot better. He's a great late round pick in relatively shallow leagues if he still appears to have a shot at the starting rotation when your draft takes place.