Stadnik was placed on the developmental squad of the Wranglers on March 18, 1984, to begin the 1984 USFL season.[9] He was later activated on April 1 after two games there.[9] He appeared in 13 games for the Wranglers in 1984 at right tackle, 11 as a starter, helping them reach the league championship with a 10–8 record.[12] He played with the Arizona Outlaws, a merger of the Wranglers and Oklahoma Outlaws, during the 1985 USFL season, appearing in 17 out of 18 games while they went 8–10.[13]
Stadnik became a free agent when the USFL folded prior to their 1986 season.[9] He returned to the NFL by signing with the San Diego Chargers on April 13, 1987.[14] He missed time in preseason due to injury and was released by the team at the final roster cuts on August 29.[15][16] On September 24, he was re-signed to the team as a replacement player during the NFL Players Association strike.[9] He appeared in and started all three strike games for the Chargers at center, helping them win each game.[4][17] Stadnik was among the first 20 alumni of Western Illinois to play in the NFL and was one of five active in the 1987 season.[18] He was released at the end of the strike, on October 20, 1987.[9] He was re-signed by the Chargers on March 4, 1988.[9] He was released again on August 3, 1988, and did not sign with another team afterwards, ending his professional career with 30 USFL games played and three NFL games played.[4][19][20]
Personal life
With his wife, Debbie, Stadnik had four children, including two daughters and then twin sons.[21] One of his daughters was a collegiate swimmer for the Gardner–Webb Runnin' Bulldogs while his two sons, Brock and Clayton, both were top high school football linemen and played with the South Carolina Gamecocks.[21][22]