Baltimore desperately needed help at the position because of injuries, and they're hoping Givens can help. Now in his fourth NFL season, the 6-foot Givens has 88 catches for 1,433 yards and four touchdowns.
He also returned kickoffs for the Rams.
The trade comes after Baltimore lost two receivers during Thursday's win over Pittsburgh. Steve Smith hurt his back and was listed as day-to-day on Saturday, and Michael Campanaro was placed on injured reserve Saturday with a back issue.
Givens was originally selected by St. Louis out of Wake Forest in the fourth round of the 2012 NFL Draft.
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