In terms of tenure, there are none in higher standing than Jackie Slater, who played 259 Games in the NFL (plus 18 more in the playoffs) for the Rams in a 20-year career that spanned from 1976 to 1995.  Earning the starting Right Tackle job to commence the 1979 season, Slater would be a fixture there starting 211 of the next 211 games he played.  Throughout the 1980s, Slater established himself in the upper echelon at his position going to the Pro Bowl seven Times and receiving three Second Team All-Pro Selections.  There will never be a more durable player in franchise history than Slater.