PHOENIX -- D-backs third baseman Jake Lamb knew he had hurt his left shoulder when he dove for, and caught, Cody Bellinger's pop foul in the ninth inning of Monday night's 15-inning marathon against the Dodgers.
Adrenaline kept Lamb in the game to take three more at-bats and score the game-tying run in the 15th with a headfirst dive into home plate, which seemed to further tweak the shoulder.
An MRI exam taken Tuesday morning showed Lamb had a sprain of the AC joint, and the team placed him on the 10-day disabled list.
Right-hander Matt Koch was called up from Triple-A to provide the team with an extra arm after running through their entire bullpen Monday.
D-backs manager Torey Lovullo declined to say how long Lamb is expected to be out.
"I don't want to predict anything one way or another," Lovullo said. "I just know that he needs some time." 

"I kind of just dove for the ball and felt my shoulder jam up," Lamb said of his ninth-inning catch. "It was killing me the rest of the game. Whether it was adrenaline or whatever, I wanted to keep going. I woke up and it was really tight this morning. I think [going on the DL is] the best decision for me and the team."
After the injury, Lamb went 2-for-3 and just missed a home run in the 12th when his drive down the right-field line was narrowly foul.
"Yeah, which was almost frustrating," Lamb said of almost hitting a walk-off homer. "Those were two of the harder balls I've hit so far and I had one arm. I was feeling the adrenaline, especially when I was hitting. And, yeah, running the bases, trying to score on Nicky's [Ahmed] double. I was trying to score any way I can."
Lovullo said he will mix and match at third in Lamb's absence, with Deven Marrero and Daniel Descalso seeing the bulk of the playing time there. Marrero got the start Tuesday against Dodgers lefty Clayton Kershaw.
Other injury news
• D-backs reliever Randall Delgado, who is on the DL with a left oblique strain, threw 20 pitches in a simulated game Tuesday and said he felt good.
• Outfielder Steven Souza Jr. (strained right pec) played catch from about 150 feet as he continues to get closer to a return.