Steve,
The Giants drafted Larry Jacobsen in the 1st Round (#24 overall) of the 1972 draft. The Giants had obtained this pick as part of the trade that sent The Sainted Fran Tarkenton back to the Vikings. I believe that the injury occurred over the 72-73 off-season. The injury actually resulted from him stepping on a glass at a pool party. Jacobsen tried returning, but was unable to push off with the injured foot. He played in 19 games the next two seasons, but was gone following 1974. (As a historical side note: Prior to his injury, I believe that we had Jacobsen slotted in for the HOF. Right next to the Connecticut Huskie great, Vince Clement.)
Lucious Selmon is the elder Selmon of which you speak. As you noted, he was an undersized NT who graduated from OU in 1974. The Patriots selected him in the 16th round of the 1974 draft, but Lucious opted instead to play for the Memphis Southmen of the newly established World Football League. When the WFL folded after two seasons, Lucious returned to Oklahoma in 1976 as the Sooners' defensive line coach. He remained at OU for nineteen seasons. He moved on to the NFL in 1995 as Tom Coughlin's DL coach in Jacksonville. He remained with the Jaguars through the '02 season. His latest and last coaching stint was in 2005 as the DL coach at Michigan State.
Lee Roy Selmon was the #1 overall pick in the 1976 draft, being selected by the expansion Tampa Bay Buccaneers. He was a six-time Pro Bowl selection in his nine years with the Bucs. In 1995, he was selected for the Pro Football Hall of Fame.
Dewey Selmon was also drafted in 1976 by the Bucs. He was a Round 2 selection, #60 overall. He played for the Bucs from '76-'80 and for the Chargers in '82. He played in no Pro Bowls, but was a 2nd Team ILB on the Associated Press' 1979 All Pro Team.
Trivia question:
What was odd about Lee Roy Selmon's selection to the HOF?
BigHitter