Sullivan missed the entire 2015 season after two back surgeries, and while the Vikings held a competition for the starting center job between him and Berger -- who started all 16 games in Sullivan's absence last season -- Berger appeared to have the job won, when he started the team's third preseason game while Sullivan watched in a baseball cap.
The team had been trying to trade Sullivan before Tuesday's initial roster cuts, as USA Today reported on Monday evening, but after the Vikings were unable to find a trade partner, they released the 31-year-old. Sullivan was due to count $5.83 million against the team's salary cap this season, which likely made him more attractive to teams as a possible free agent than as a trade target.
"Our entire organization appreciates everything that John Sullivan has done for this franchise," Vikings general manager Rick Spielman said in a statement. "Sullivan led our team, not only with how he played the game, but also with how he handled himself in our community. We wish John Sullivan and his family nothing but the best as they move forward."
Sullivan was named the Vikings' Community Man of the Year in 2013, for his work with the University of Minnesota Masonic Children's Hospital.