The Minnesota Vikings, already depleted at the safety position, put Antone Exum on injured reserved Tuesday. With starters Harrison Smith and Andrew Sendejo nursing injuries, the team signed a pair of safeties: free agent Shaun Prater and, off the practice squad, Anthony Harris.
The Vikings also released defensive end Justin Trattou to make room on the 53-man roster.
Exum started against the Seahawks on Sunday and played 66 snaps on defense, second-most on the team. But late in the game he fractured a rib and injured the AC joint in his shoulder. Exum had five tackles and a forced fumble vs. the Seahawks and finishes with 13 tackles this season.
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Prater played for the Vikings in 2013-14 before being cut before the start of the 2015 season. He played in one game with Indianapolis this year.
Harris, an undrafted free agent from Virginia, has been on Minnesota's practice squad all season.
Trattou has played 10 games for the Vikings from 2013-15, including two this season.
Starting strong safety Andrew Sendejo missed the game against Seattle while starting free safety Harrison Smith saw just 10 plays on defense before exiting with a hamstring injury.