Mike Gillislee for Martavis Bryant

I got this offer where I would be giving up Gillislee for Bryant. This is a half point format. I am currently 4-0 and my other running backs are Lev Bell, Lenny Fournette, Duke Johnson and Smallwood. Whereas my WRs are Watkins, Diggs, Michael Thomas, Maclin, Garcon, Ted Ginn Jr and Josh Doctson. What are your thoughts?