PHOENIX -- Robbie Ray admitted that he was a little nervous about the state of his back after being forced to leave Wednesday afternoon’s game against the Rockies before the bottom of the third inning.

The left-hander’s mind was put at ease Thursday when an MRI exam of his back confirmed the team’s initial diagnosis that he simply had experienced back spasms.

“Yesterday my back was feeling pretty sore and to hear that it’s not anything serious -- no tear, no strains, nothing like that -- is encouraging,” Ray said.

The D-backs placed Ray on the 10-day injured list to let him have time to get treatment and make sure he is 100 percent next time he takes the mound.

“The comforting factor for me in the whole thing is that he’s going to be 100 percent for the rest of the year,” D-backs manager Torey Lovullo said. “That’s what I’m feeling.”

With Ray’s short outing Wednesday on the heels of a four-inning stint by starter Zac Gallen on Tuesday, the D-backs needed some reinforcement in the bullpen.

With that in mind, they called up right-handers Jon Duplantier and Stefan Crichton from Triple-A Reno and optioned outfielder Tim Locastro to Reno, giving them 13 pitchers on the roster.

While Duplantier is viewed as a starter long-term by the organization, the plan is for him to pitch out of the bullpen for now.

This is the fifth time Duplantier has been called up during the season. He has made eight appearances (three starts).

“We are very mindful and cautious with a young pitcher going back and forth as much has he has,” Lovullo said.

Lovullo added that no decision had been made as to who would take Ray’s turn in the rotation. Taylor Clarke, who has made 14 appearances (13 starts) for the D-backs this season, remains a top candidate at Reno.

“We’ve got four days to figure that out,” Lovullo said.

Ray’s spot next comes up Monday against the Rockies at Chase Field.

Crichton, 27, has held opponents scoreless in 11 of 13 relief appearances for the D-backs this season with a 3.24 ERA in 16 2/3 innings, a .169 opponents average, 15 strikeouts and a 0.90 WHIP (10 H, five BB). In 32 relief appearances for Reno, he is 3-3 with one save and a 4.03 ERA 51 1/3 innings.