HELL NOOO!!!!!! This is a keeper so never give up your best asset that's a top tier RB that's super young. Martin has a great career ahead of him. Welker is way older and WRs are way easier to come by. Martin's value is the lowest it'll ever be so don't trade him this season if ever. Ever hear the saying buy low sell high? The other GM is trying to but low on Martin. Don't make the bad mistake of selling low.
Edit: In a keeper league Martin's value is higher than AP's.