Of course, some deals are a lot bigger than others. However, teams need to have an idea what they are going whenever they sign a player or make a trade.
Right before the 2009 season, the Giants traded ineffective left-handed reliever Jack Taschner to the Phillies for back-up catcher Ronnie Paulino. At the time, the move made a lot of sense for the Giants, because Taschner had received more than his fair share of opportunities at the major league level from the Giants, and the team had better (younger and cheaper) options for left-handed short men in their system.
Paulino was no world-beater, but he had been the Pirates regular catcher in 2006 and 2007, where he hit fairly well (.754 and .703 OPS numbers). Paulino had a bad year in 2008 at the major league level, and appears to have had some injury problems since he played some time at the rookie league level, which usually means a rehab assignment. However, he had a .923 OPS in 30 games at AAA Indianapolis that year.
The Pirates felt they weren’t getting enough effort out of Paulino (according to wikipedia), however, and traded him to the Phillies in December 2008 for AAA catcher Jason Jaramillo. Jaramillo does not appear to be as good a hitter as Paulino, but he’s a little younger and he was good enough to be an adequate back-up catcher for the Bucs in 2009 (.673 OPS).
Meanwhile, after the Phillies sent Paulino to San Francisco for Taschner, the Giants immediately flipped Paulino again (his third trade of the off-season) to the Marlins for Class A pitcher Hector Correa. Clearly, the Giants thought they were getting another good young arm in Correa, but he apparently did not pitch at all in 2009, almost assuredly due to injuries.
Meanwhile, Paulino played 80 games for the Marlins in 2009, hitting .272 with a .762 OPS. A back-up catcher with a .762 OPS (and a career major league OPS of .724) is a valuable thing.
I write about this in part because I watched 2010 Giants’ back-up catcher Eli Whiteside look completely over-matched by the Braves’ Derek Lowe on TV last night. Whiteside has a reputation as working well with pitchers and being good in the clubhouse, but he doesn’t block balls in the dirt well, and he just isn’t a major league hitter.
Whiteside had a career major league OPS of .598 entering this year, and a not much better minor league career OPS of .681. In other words, it seems fairly obvious that the Giants would have been much better served if they had held onto Paulino when they got him for a redundant player in March of 2009.