He has the same problem that a few other former-college-star WRs have: in order to stay focused and motivated, he needs to get fed the ball and be involved on most plays. This is why he sometimes runs great routes and flashes amazing potential, only to lose focus after he had been on the bench or asked to block for 10 minutes. The brain power and discipline is just not there for a more mature, professional behavior. The same de-motivation probably also translates into the poor practice habits we hear about ("Why do I bother, they don't give me the ball enough anyway") and all the other things we don't see as clearly ("I got myself a route-running coach over the summer, but then decided not to bother")
I don't think most of this is fixable, although, in theory, some clever coach + the inevitable advent of age might turn him around. His fifth-year option got picked up, but he is nowhere near worth the money, so he would most likely get cut. Someone will take a flier (Cleveland? Kansas? Oakland? Dallas?) with the intention of using him in a much more dynamic, Percy-esque role that doesn't require precise route-running. From that perspective, Zimmer's Vikings are a terrible fit and you know Zimmer won't change his views of how a WR should play, but another coach might be more flexible.
That still doesn't solve the above problem, but if your bench is deep enough, he could be solid value in 2016. It's not like he is worth much today; I have him in one league that rewards rushing yards a bit more and I keep getting offers for a 3rd rounder + rejections for a 2nd rounder.
