MRI shows Diamondbacks' Walker injured UCL

Arizona Diamondbacks right-hander Taijuan Walker, who went on the 10-day disabled list on Sunday, has an injured ulnar collateral ligament.

He was originally sidelined with right forearm inflammation, but an MRI showed additional damage.

The team is unsure if the UCL is torn, which usually requires Tommy John surgery and an extended recovery.

"I apologize for being vague, but it's very vague right now," Diamondbacks manager Torey Lovullo said, per MLB.com. "Every bit of information that we've gotten is vague. I know in the coming days I'll have more information about what the next steps are."

"This information came as a surprise to me," Lovullo said. "I thought that he would be OK. It just goes to show you that you can't ever be too safe. I want to believe that he's going to be OK, but he's being examined, and where it takes him from here we're not sure. It's still wide open."

Walker departed Saturday's game against the Los Angeles Dodgers after the second inning due to forearm soreness.

Arizona recalled right-hander Silvino Bracho from Triple-A Reno to fill the roster spot. Bracho compiled a 5.66 ERA in 21 games for the Diamondbacks last season.

Walker has a 3.46 ERA in three starts this season. He went 9-9 with a 3.49 ERA in 28 starts last season in his first campaign with the Diamondbacks.

--Field Level Media