Trading Welker at least makes sense. With two WRs better than him on the roster and two TEs as an important part of the offense, his playing time is going to go way down. He's 30, and he's in the last year of his contract.
Hernandez, on the other hand, looks to see his playing time go way up. He's one of the premiere receivers out of the TE position, and teams will have to worry about Gronkowski too.