When the Mets acquired Luis Castillo from Minnesota on 7/30/07, Castillo was hitting .304/.356/.352 for the Twins. The move was not one of necessity but rather of convenience. The cost -- minor leaguers Drew Butera and Dustin Martin -- was low, and the Mets already had a fairly capable young second baseman in Ruben Gotay. The incumbent keystoner, Jose Valentin, was equal parts injured and awful in his 183 plate appearances prior to landing on the disabled list for good.
Reaction to the trade was mostly favorable, with the dissenters generally preferring more youth (Gotay) and less wonky knees (Castillo).
Castillo was as-advertised, maybe even a little better. His ailing knees kept him out of action on occasion and led to some uncomfortable looking slides on the basepaths, but his offensive contributions actually exceeded expectations. He hit .296/.371/.372 in 231 plate appearances with the Mets, each higher than his career averages of .294/.368/.358. His .271 EQA was far from horrible, and he was successful on ten of twelve basestealing attempts (83%).
Castillo's biggest problem at the plate is his utter (and notorious) lack of any power to speak of. He collected just eleven extra-base hits with the Mets, posting a dreadful .076 isolated power (SLG minus AVG), and that was an improvement over his performance with the Twins.
Castillo has never slugged higher than .397 in twelve full or partial seasons in the big leagues, and he isn't likely to do it in any of his remaining seasons, either. That said, it's hard to be disappointed with his power output since we all knew from the get-go that he wouldn't be delivering anything in that particular department.
Well, sure-handed pretty much sums it up. Injury and age have robbed Castillo of the range he once had, but he still knows how to play the position and he still makes all of the routine plays and the occasional brilliant one.
Fans rated him an overall 68 in Tangotiger's The Scouting Report, good for eighth among big league second basemen. Oakland's Mark Ellis and Arizona's Orlando Hudson were tops in their respective leagues. Each defensive score represents an aggregate of subjective grades, but in general the fans' eyes correlate well with many of the more widely-accredited defensive metrics.
Castillo is a free agent this offseason and is likely to be a Type A one at that. The Mets are probably in the market for a second basemen unless they are willing to give Gotay a shot next year. Castillo might be a reasonable buy at two years and $12 million, but if he brings back a first round draft pick as compensation for signing with a different team (assuming the Mets offer him arbitration), that might be just as good.
I won't lose any sleep if the Mets decide to bring Castillo back. He still does a number of things well at the plate and he is a very reliable, if unspectacular, defensive infielder. His on-base skills have plenty of value in front of the Mets' big bats even if he is just a Punch and Judy hitter.
If I'm the GM I would probably let him walk, while understanding that the Mets could do far worse.