As some have said... sign him up for pre-season and if he impresses ink him to a non-guaranteed contract and let him play in the DL.
I would even give him some small bonus incentives to get him to lose some weight or decrease his body fat %.
This is a kid who should have stayed in college a few more years if possible.
No man is happy without a delusion of some kind. Delusions are as necessary to our happiness as realities- C.N. Bovee