CK makes an interesting point re a potential leap of Matthews over Gibson and one that I agree with.
Extending from this though... if Tyms and Binns or anyone else steps to the fore, I wouldn't be surprised to see Gibson be up for a trade bait discussion... considering you would then have, taking CK's suggestion; Wallace, Hartline, Matthews then the question would arise of why would you pay Gibson what you're paying him to be the 4th WR.
This 3 through 6 spot WR discussion is going to be fascinating to watch. I just hope that Binns doesn't turn into a legawho situation?