Greer left Toronto following the 1985 season for the NFL, playing with Cleveland (1986), San Francisco (1987-89) and Detroit (1990). He earned two Super Bowl rings with the 49ers – becoming the first player to achieve the championship honors in the CFL and NFL. He finished with 38 catches for 640 yards, averaging 18.2-yards per catch, with four touchdowns over 50 career games in the NFL.