The Vikings announced that they have placed safety Antone Exum on injured reserve, brought back safety Shaun Prater and promoted rookie safety Anthony Harris from their practice squad.

The moves come two days after three Vikings safeties suffered injuries in a 38-7 loss to the Seahawks. Exum fractured a rib and injured the AC joint in his shoulder. Starter Harrison Smith hurt his hamstring in the first quarter and did not return. And backup Robert Blanton injured his knee.

None of those safeties practiced yesterday, nor did Andrew Sendejo. But Sendejo was the only one of seven players back in the mix for Tuesday's practice after missing Monday.

Nose tackle Linval Joseph (foot), linebackers Anthony Barr (groin/hand) and Brandon Watts (ribs), and safeties Robert Blanton (knee) and Harrison Smith (knee/hamstring) were still out.

Prater spent time with the Vikings during the 2013 and 2014 seasons. He was one of the team's final roster cuts this summer. He had a brief stint with the Colts earlier this season but was released. He is capable of playing both cornerback and safety and is solid on special teams.

Harris joined the Vikings this spring as a rookie free agent after he went undrafted out of Virginia. He, too, was one of the team's final roster cuts, but he has spent the entire season on the practice squad.

To make roster room, the Vikings waived defensive end Justin Trattou.