I'm not worried in the least about Wes being a very good WR2 for any game he starts. I am, however, tremendously worried that he suffers some sort of setback and misses a chunk of games. Basically, if you have him, you need to either be deep at WR or handcuff him with Edelman. Edelman was a bigtime possession receiver for the handful of games that Welker missed last year and I would expect the same this season. He was invisible when Wes was active however.
Bump him down draft boards a little based on the injury risk, but start him as you would have last year pre-injury.