Iannetta was hit in the face by a Johnny Barbato pitch in the seventh inning of Friday night's game against Pittsburgh. Iannetta suffered a split top lip, cracked teeth and a broken nose.
He was taken to a hospital to be checked for head trauma, but was back with the team on Saturday.
Diamondbacks manager Torey Lovullo said Saturday that tests for a concussion were negative, but Iannetta was still being monitored.
On Sunday, Iannetta went through a workout, and after further evaluation the Diamondbacks decided to send him to the DL.
"I got lucky on all accounts," Iannetta said Sunday, speaking for the first time since the injury. "It could have been a lot worse than it really was."
Iannetta received stitches in his upper lip and suffered a couple of fractured teeth and a nose fracture. He said he'll eventually need to have the damaged teeth repaired.
Barbato and Iannetta exchanged texts after the incident and the Diamondbacks catcher said there are no hard feelings between them.
"He said, 'I'm sorry. No one feels worse than me.' I said, 'It happens. Keep your front shoulder closed next time. The ball won't sail as much.' It was nice of him to reach out," Iannetta said.
The Diamondbacks called up reliever Silvino Bracho from Triple-A Reno. Iannetta's designation is retroactive to Saturday.
Information from The Associated Press was used in this report.