You should trade for him if the guy that has him is willing to trade him at a bargain price. Reggie Wayne for last season's best fantasy player is a bargain IMO. But before you pull the trigger, what do the rest of your WR's look like? Do you have depth there?
Also you have to look at the playoff weeks. Usually they're in week 14-16, so you gotta look at the opponents of the Colts and Seahawks for those weeks. Look at who has easier matchups.