The Bills were awarded Simms on Friday, a day after he was cut by the New York Jets. He spent two seasons in New York and is reunited with former coach Rex Ryan in Buffalo.
The 26-year-old had 195 yards passing with one touchdown and an interception in four appearances, including one last season.
Tuel's two-year tenure is over in Buffalo. He made the Bills as an undrafted rookie in 2013, and struggled in two appearances, including a start in a 23-13 loss to Kansas City. Tuel spent last season on the practice squad.