Russell Sheppard new deal with Panthers 3 years 10.5 million

I'm trying to come to grips with this. I thought he was getting a much bigger package than that. I don't get it. $3.5 million per year for a productive no.4 WR and special teams ace.

Then we turn around and pay Josh Robinson $3.25 million per year and he is just a special teamer with not much value coming off the bench. Does this make sense to anyone else? Why not keep Shepard instead of Robinson especially considering our lack of depth at WR.