Vikings cornerback Mekhi Blackmon suffered a torn ACL during the team's first training camp practice on Wednesday, according to a league source.

Blackmon went down with what appeared to be a leg injury at practice and did not return. Athletic trainers tended to him on the sideline for several minutes before he walked with them slowly into the TCO Performance Center building.

Blackmon, a third-round pick out of USC in 2023, appeared in 15 games last season, starting three. He had one interception, eight passes defended, three tackles for a loss and one fumble recovery.

The Vikings entered training camp with questions at cornerback, with Blackmon and third-year player Akayleb Evans trying to win significant roles. The team had hoped rookie Khyree Jackson would be a factor on defense as well, before the fourth-round pick was killed in a July 6 car crash.

Veteran cornerback Shaq Griffin was signed as a free agent as defensive coordinator Brian Flores planned to include more man-to-man coverage and talked about playing Byron Murphy Jr. more in the slot. Griffin stepped into a starting role during spring practices.

The Vikings on Tuesday re-signed cornerback Duke Shelley, who made multiple big plays in limited opportunities during the Vikings' 13-4 season two years ago.

"I didn't want to leave here," said Shelley, who signed with the Raiders before last season and then joined the Rams. "I feel like this is home for me. I feel the guys welcomed me back with open arms. It just feels like I was away from home a little bit."

In other injury news Wednesday, running back DeWayne McBride was removed from the non-football injury (NFI) list and practiced. Meanwhile, head coach Kevin O'Connell said a left knee injury is what has landed special teams standout NaJee Thompson (also a cornerback) on the physically-unable-to-perform (PUP) list. O'Connell said Thompson's injury doesn't appear to be serious.