The Vikings have officially released veteran offensive guard Charlie Johnson.

The 30-year-old spent the past four seasons with the Vikings, starting 61 of 64 games. In 2014, he struggled at left guard before missing two games late in the season with an ankle injury. Johnson returned for the season finale, and it will likely end up being his final game in a Vikings uniform.

Johnson signed a two-year deal with the Vikings last offseason to stay with the team. By releasing Johnson, the team cleared $2.5 million in cap space without any dead money staying on the cap.

Johnson is now a free agent and can sign with any team.

Johnson's release was not a surprise. The Vikings are expected to prioritize improving the offensive line this offseason after that group disappointed last season. With the other four starters from the 2014 season opener expected to return, the team could add a veteran guard in free agency, select one in April's NFL draft or both.

Veteran backups Joe Berger and Vlad Ducasse are scheduled to join Johnson in unrestricted free agency on March 10. Backup tackle Mike Harris is a restricted free agent.