Although the audition went well, the Ravens aren't expected to make an immediate roster move at this time.
Ravens tight ends Ed Dickson (four drops, one catch) and Dallas Clark (seven catches on 12 targets, one dropped touchdown) had shaky hands during a 49-27 loss to the Denver Broncos to open the season.
At 6 feet 4, 267 pounds, Mulligan is primarily a blocking tight end. He has played in 50 games with 20 starts and 14 catches for 144 yards and one touchdown.
He spent his first NFL season on the practice squad of the Miami Dolphins and the Tennessee Titans, and then he was claimed off waivers in 2009 by the Jets after being released by Tennessee during training camp.
Ballard, 25, was cut by the Patriots last month after spending last season with them recovering from a torn anterior cruciate ligament in his left knee suffered when he was playing for the Giants in Super Bowl XLVI against the Patriots.
The 6-foot-6, 275-pounder caught 38 passes for 604 yards and four touchdowns in 2011 while playing for the Giants.