Trestman moved to the National Football League and coached running backs with the Minnesota Vikings in 1985 and 1986. He served as quarterbacks coach first with the Tampa Bay Buccaneers in 1987 and then the Cleveland Browns in 1988. In Cleveland he again coached Kosar and the team finished 10–6 and made the playoffs. His promotion to offensive coordinator in 1989 was made before the team named Bud Carson as Marty Schottenheimer's successor as head coach. Kosar passed for 3,533 yards and 18 TDs that season, while wide receiver Webster Slaughter had a franchise record 1,236 receiving yards. Trestman was dismissed after the Browns' third loss in the AFC Championship game in four years, primarily due to his strained relationship with Carson.