I don't think there has been someone like him before or after (no college experience) in the modern era. Think about going from basically high school to being an All Pro in the NFL.
From the Bay State Titans (semi-pro) page:
Discovery of Eric Swann The Titans claim to fame was the reclamation of 19-year old defensive lineman Eric Swann. Swann was a fast and enormous (6′ 5″, 320 lb.) pass rusher who never played a down of college football. Swann reportedly had Attention Deficit Disorder. Recruited to play for North Carolina State in 1989, he couldn’t land the necessary minimum SAT score to play for the Wolfpack. He wound up working a minimum wage jobs on the grounds crew of the North Carolina State Fairgrounds. A chance encounter with a scout from the New Orleans Saints led him to Dick Bell, a football agent who also moonlighted as the General Manager of the newly formed Titans.
Swann dominated the MLFS in the summer of 1990. Stats from the league are sketchy at best, but press reports claim Swann piled up 72 tackles, 11 sacks and four blocked field goals in Bay State’s 10 games.