Aaron Thompson

He's a long shot to win a spot in the bullpen and likely just adds depth at Triple-A. Thompson had a 7.04 ERA in just four appearances (one start) in the majors with Pittsburgh. He struggled at Triple-A with a 5.16 ERA. He had decent control (2.15 BB/ 9 IP) in the minors but had another mediocre strikeout rate (5.5 K/9 IP). He wouldn't appear to have much upside as a result. He did perform much better against left-handed batters (8.5 K/9 IP and 2.88 FIP), so perhaps he can win a lefty specialist role in the majors.

Thompson's third season at Double-A was no better than his first two, but the Nationals moved him up a level anyway. There isn't anything in his statistical profile to indicate a leap is imminent. At this point, Thompson is a crafty lefty still in search of his craft. Look elsewhere if you're trying to stash away minor league upside in a deep keeper format.

The former Marlins prospect pitched better in six starts at Double-A after being acquired in the Nick Johnson deal, but given that he was at the end of his second full season at that level you'd hope he could at least hold his own. He's still got youth, moxie and left-handedness on his side, but so far he hasn't looked like a pitcher who's ready to make a leap.

Thompson hit the metaphorical wall at Double-A, and his numbers regressed across the board. Double-A struggles have happened to better 21-year-olds than him, however, so a year to regroup and get back on track might not be the worst thing for his long-term development. Thompson's best asset to date has been his intelligence, not his good-but-not-great stuff, and those mound smarts will be put to the test in his second crack at Double-A. If he shows he can adapt and overcome, don't be surprised if the Marlins reward him with a September call-up.

The Marlins' High-A affiliate in Jupiter plays in a pitcher-friendly park, but Thompson's home run rate (two in 115 innings) was still incredible regardless of his surroundings. His pitch assortment (fastball that can touch the low 90s, slider and change-up) doesn't set scouting hearts a-flutter, but his control, mound smarts and ability to keep the ball down set him apart from the average "finesse lefty" prospect. He'll be a 21-year-old tackling Double-A for the first time in 2008, and the Marlins will be less likely to rush him than some of their other young pitchers like Chris Volstad. A September cup of coffee is probably the most he can hope for this year.

Although he could have been a little less hittable Thompson had what can only be considered a successful full season debut, posting a better than 3:1 K:BB ratio at Low-A as a 19-year-old. His fastball has enough pop for Thompson to avoid being typecast as a finesse lefty, and a big season at High-A will have him shooting up prospect lists. Keeper league owners should be aware that given his age, and the pitching depth in the Marlins system, he would have to utterly dominate to get fast-tracked up the ladder. A 2009 major league ETA isn't out of the question even if he continues to pitch well.