Er, Russell Martin for Cervelli whose overacting has tired out the umpires (never mind opponents are finally pitching at him and it shows by his offensive stat decline)...
I mean, this is a no-brainer. You have Martin and Montero platoon while Posada limps out the last year of his career (cause he ain't staying healthy for a full season). Even if Montero turns out to be Johnny Bench defensively (and he ain't) you can still use Russell defensively and move Montero to DH, giving Posada an off day to teach base running skills.
