Making up for the loss of starting pitcher Zack Greinke just got a little bit harder for the Los Angeles Dodgers, as left-hander Brett Anderson will undergo surgery for a bulging disc in his back and be sidelined for three to five months.

Anderson felt discomfort after a live batting-practice session Tuesday and an MRI was performed on his back Wednesday revealing the injury. Anderson previously had back surgery in 2014 as a member of the Colorado Rockies to repair a herniated disc.

Dodgers manager Dave Roberts said Thursday morning that Anderson is expected to be lost for three-to-five months. Surgery will take place in Phoenix and be performed by doctor Chris Yeung.

Brett Anderson will be sidelined three to five months after having back surgery. AP Photo/Morry Gash

"I was shocked," Roberts said. "Talking to him two days ago and then yesterday, he just thought it would be a couple of days and would subside. But obviously to be cautious we took some images, some pictures. That's what we came up with."

Anderson agreed to a $10 million, one-year contract with the Dodgers in December 2014 and accepted a $15.8 million qualifying offer from Los Angeles last November.

Anderson was scheduled to make his Cactus League debut Sunday, lining him up for the rotation's No. 4 spot behind Kenta Maeda. The No. 2 starter behind staff ace Clayton Kershaw was lined up to go to another newcomer in Scott Kazmir.

Both Kazmir and Maeda were added after Greinke's free-agent departure to the Arizona Diamondbacks. While neither pitcher is expected to perform at Greinke's level from last season (19-3, 1.66 ERA), adding two starters after the departure of one is what has given the Dodgers a little extended starting depth this season.

The Dodgers had Alex Wood lined up for the rotation's No. 5 spot, but he could be moved up to the fourth spot. Candidates to move into the rotation now include Mike Bolsinger and Brandon Beachy.

"It's one of those things where we didn't think our depth would be tested so early," Roberts said. "But obviously with Alex and Beachy and Mike Bolsinger, we have depth and those guys are going to have to step up. We will be evaluating and every day is a test. We will evaluate."

Anderson, who also had Tommy John surgery in 2011, did not feel his discomfort from Tuesday's pitching session would lead anywhere near to an arthroscopic procedure.

"I think he said that it wasn't near the sensation that it was before," Roberts said, comparing his back injury in 2014 to this one. "It was something that we would take two or three days and let it subside. I think he was as surprised as anyone."

It is not the only starting pitching concern for Roberts as recovering starter Hyun-Jin Ryu is also experiencing a hiccup in his return from shoulder surgery last May. Ryu, who isn't expected to return to the Dodgers until May, hasn't thrown a bullpen since Friday because of shoulder soreness. Starter Brandon McCarthy, who underwent Tommy John surgery last year, is expected to return in July.

Information from The Associated Press was used in this report.