tough call. Seems like Harvin just gets up for big games. Is he consistently gonna be a guy that just wants to play in playoff games or games against his ex team? I doubt they would sit him, but maybe the guys that got you here should be suited up for the playoffs.
A rusty player could possibly be a negative but i don't anticipate he will be a huge part of their game plan. They may try to get him a few targets just to Get him back in the flow
The only danger is if he can't catch a ball thrown to him that deflects to a defender for a pick. That risk can't outweigh the potential for upside. He is an explosive player that threatens to blow by defenders every time he has the ball and will force them to know where he is at all times and swarm to him. He will also likely get their best defenders leaving the rest of the WR's likely either in man or at least with lessor coverage than had they not played him.