LOS ANGELES -- The Dodgers’ pitching staff suffered another major blow Saturday as the team placed right-hander Dustin May on the 15-day injured list, retroactive to Sept. 22, with low back tightness.

Though the Dodgers are listing it as a back injury, manager Dave Roberts said the injury is the left side of May’s body. Roberts said he first heard about the injury following May’s latest start against the D-backs on Wednesday. 

“Not ideal. Not ideal. Not what we were planning on,” Roberts said. “I thought we’d managed him well, and obviously with Dustin coming off Tommy John, the arm was the thing that we were very mindful of. So to have this setback, it’s where we’re at. We got to kind of deal with it and move on.” 

Roberts said they expect May to play catch over the next few days. Their hope is he’ll be ready to return in time for the NL Division Series in about three weeks. 

“If you’re looking at the buildup to get him back, IL made sense,” Roberts said. “He should be back the week after the season throwing and pitching again. We’re expecting him to be back for the DS. But that’s just the right thing to do right now.”

May missed the first four months of the regular season while recovering from Tommy John surgery. Since returning, May hasn’t been able to find consistency, delivering three solid starts and three rough outings. Against the D-backs he allowed five runs over four innings, his shortest start of the season.

While the Dodgers are hopeful to have May healthy in time for the postseason, the injury adds another concern to the club’s pitching plans. The Dodgers will rely on Julio Urías, Clayton Kershaw and Tyler Anderson in the starting rotation. They’ll need a fourth pitcher to emerge as a dependable option.

Andrew Heaney, Tony Gonsolin and May are the options. Heaney has been bitten by the home run ball over his last handful of starts. Gonsolin, on the other hand, is still trying to make it back from a right forearm injury. He’ll pitch two innings for Triple-A Oklahoma City on Tuesday.

With May slated to miss time, it’s unlikely that he’ll be able to handle a starter’s workload, even if he does return in time for the postseason. May is also a bit limited in roles, given the Dodgers will remain mindful of the fact he underwent major surgery just a year ago. 

The Dodgers are confident they’ll be able to withstand yet another major loss, but this certainly puts another wrench in Los Angeles’ postseason pitching plans, even if the best-case scenario comes true and May is able to return in time. 

“I think that if you talk about the role, certainly, that’s sort of contingent on how long he’s going to be down,” Roberts said. “But I think it’s fair to say it’s shortened, as far as the length that he can give us. But if he’s healthy, then it’s still a weapon.”