In September 1966, shortly before the start of the 1966 NFL regular season, the Lions' head coach Harry Gilmer placed Pietrosante on waivers. Days later, he was signed by the Cleveland Browns, who had lost the services of Jim Brown after the 1965 season. However, Pietrosante saw limited action for the Browns, carrying the ball only 17 times for 93 yards during the 1966 and 1967 seasons. In July 1968, Pietrosante announced at age 30 that he was retiring from the NFL.