Peterman, a rookie fifth-round pick, replaced Taylor with less than five minutes remaining in a 47-10 loss to the New Orleans Saints. Taylor completed nine of 18 passes for 56 yards before being benched.
Peterman went 7-for-9 for 79 yards and a touchdown over the final two drives for the Bills, who have lost two straight.
“We are in the playoff hunt, and we are always focused on becoming the best team possible,” McDermott said Wednesday. “We were made for better than 5-4.”
The Bills haven’t made the playoffs since 1999, the longest active drought in the NFL and the longest in franchise history.
McDermott said he remains confident in Taylor, but he decided to make the move to see if Peterman can make Buffalo a better team.
“I’ve been impressed with the maturity from Nathan Peterman,” said McDermott, who on Monday maintained Taylor would continue to start. “I’m comfortable making a calculated risk to try and get us where we need to go.”
The Bills, led by veteran offensive coordinator Rick Dennison in his first year with the team, rank 28th in yards per game (292.0) and 20th in points per game (20.4). Against a Saints defense that ranked 15th in yards allowed per game entering Sunday (326.6), there was a clear problem Sunday for Buffalo’s offense.
Taylor’s 56 passing yards and 33.6 passer rating were both the lowest in his 38-game career as Buffalo’s starter. His career-worst outing came despite the Bills debut of wide receiver Kelvin Benjamin, acquired in a trade last month, and the return of tight end Charles Clay from a monthlong absence because of a knee injury.
Taylor is averaging just 6.6 yards per attempts this season (26th in NFL) and has thrown 10 touchdown passes, the third-fewest in the NFL among the 20 quarterbacks with at least 300 dropbacks, according to ESPN Stats & Information.
He restructured his contract on March 10, and only $1 million of his $10 million base salary for 2018 is fully guaranteed. Taylor is scheduled to receive a $6 million roster bonus on March 14, 2018.
Peterman led the Bills on a six-play, 75-yard drive ending in a 7-yard touchdown pass to tight end Nick O’Leary before the Saints ran out the clock to end the game.
“I thought he did some good things,” McDermott said of Peterman after Sunday’s game. “Moved the offense there. Obviously, got us into the end zone, so that was a positive.”
Peterman was selected in the fifth round of the draft after splitting his college career at Pittsburgh and Tennessee.
ESPN’s Mike Rodak and The Associated Press contributed to this report.