Jesus...was hoping this was some kind of spoof thread.
The Lieutenant seemed like the typical Red Sox FA signing of a particular era; the guy who was signed coming off a career year or because he had pitched well against the Sox,and is inevitably a disappointment.
For at least a little while, he was a Yankee killer, and he's got a ring. Sad story.
What was typical? Good? He was a pretty good 5th starter signed to short money, and pitched 300 innings of around league average ball for a $2 million a year. I'm not sure what the expectations some had for a guy with a 94 ERA+ at the time he signed his contract, but he didn't come to town with the expectations nor price tag that John Burkett did, who was a classic "career year" guy coming in to be the number 2 starter (Lowe certainly surprised many). I'm not sure why anyone would be disappointed by Castillo's first stint with the team.
That said, one of my favorite things about Castillo was after the 2001 season (I believe) he had an interview on mlb.com in which he was asked what could be done to improve the game, and he mentioned speeding up the game by having the umpires enforce the pitchers getting back to the mound and throwing their next pitch. If one recalls, Castillo was a notoriously slow worker on the mound.