Peterman joined Buffalo in 2017 as a fifth-round pick and appeared in four games during his rookie campaign, going 1-1 in two starts.
He led the Bills during this past preseason in yards passing (431), completion percentage (80.4) and passer rating (124.7), adding three touchdowns with an interception en route to winning the job. The Bills were apparently comfortable enough with Peterman to trade quarterback AJ McCarron over the weekend to the Oakland Raiders in exchange for a 2019 fifth-round pick.
Allen, the seventh overall pick of the 2018 draft, finished the preseason completing 24 of 44 passes (54.5 percent) for 210 yards and two touchdowns. He was sacked seven times and held an 82.58 passer rating.