1.) Leonard Fournette - Running Back
The Bills already have not just three running backs that are more than likely to make the roster, but they each bring some skill set that will benefit the Bills. James Cook provides a catch out of the backfield presence and both Damien Harris and Latavius Murray can run into contact and push for extra yardage against contact. However, running back Leonard Fournette not only is a downhill runner but he can also serve as a pass-catcher out of the backfield. On top of that, he is only 28 years old.
Fournette has played with the Jacksonville Jaguars and Tampa Bay Buccaneers the last six years of his career and has only rushed for over 1,000 yards twice. In Buffalo, Fournette does not need to be the main back in the backfield with the emergence of James Cook.
Now if the Bills were to sign Fournette, that would more than likely mean that Latavius Murray might be pushed out of the running back room. With this hypothetical signing, the Bills would be getting themselves a back who can still produce as a fantastic player within a rotation.