According to WEEI's Alex Speier, when Hideki Okajima's 2009 vesting option triggered it also guaranteed that the reliever is under team control through 2012 if the Red Sox want him. There had been some debate about whether Okajima would become arbitration-eligible after his current contract; the answer is yes.
Also, WEEI's Rob Bradford notes that J.D. Drew is entering the phase in his five-year contract where certain injury situations would allow the Sox to void the last two years of this deal. It seems unlikely, though.