In 1973, his fifth year in the NFL, he became the starting center of the Bills, replacing Remi Prudhomme, splitting time with Bruce Jarvis, centering between Reggie McKenzie at left guard and Hall-of-Famer Joe DeLamielleure at right guard, for a fine 9-5 team, when O.J. Simpson became the first running back to rush for over 2,000 yards. In 1974, Montler won the job away from Jarvis, starting in all 14 games for another 9-5 season. The Bills lost ground in 1975 with a won-lost record of 8-6, despite having the best offense in the entire NFL with 420 points (30.0 points/game). For the second year in a row, Montler played all 14 games between McKenzie and DeLamielleure in the stout middle of the Bills offensive line. Although the same trio played together in all 14 games in 1976, the team sagged to 2-12, an offense worth 20th place in scoring and a defense 24th in points allowed. Things had to change. Montler was replaced by 5-year pro Willie Parker (offensive lineman).