After Karlos Williams was released by the Bills after showing up out of shape , he stepped in and took the role of Bills ' backup running back .
On January 4 , 2016 , the Bills signed Gillislee to a contract extension .
After Karlos Williams was released by the Bills after showing up out of shape , Gillislee stepped in and took the role of Bills ' backup running back .
On January 4 , 2016 , the Bills signed Gillislee to a contract extension .