Mulligan will compete with those two players, along with Jordan Thompson and Casey Pierce, for a roster spot. The 31-year-old went undrafted out of Maine and has bounced around the league ever since. He spent the first three seasons of his career with the New York Jets from 2009 to 2011. He then went to St. Louis in 2012, New England in 2013, Tennessee, Arizona and Chicago in 2014 and Buffalo last season.
In all, he's played 81 games, making 17 catches for 162 yards and two touchdowns. He hasn't caught more than two passes in a season since 2012, when he had a career-high eight catches for 84 yards and one of his career scores. Last season he had one catch for two yards and he had no catches in 2014.
At 6-foot-4, 267 pounds, he is primarily going to be a blocking tight end -- possibly insurance for Pettigrew if his knee doesn't recover well from a torn ACL suffered last season.