First baseman Adam LaRoche, who was placed on the disabled list in late May because of a torn labrum in his left shoulder that made hitting painful, will have season-ending surgery on Thursday, General Manager Mike Rizzo said following Tuesday’s game.

Nationals’ medical director Wiemi Douoguih will perform surgery in Washington on LaRoche, Rizzo said. While the extent of the injury and its rehabilitation are unknown until LaRoche is under the knife, Rizzo said he hopes LaRoche will be back in time for next season.

“If all goes right,” Rizzo said, “he will be 100 percent by the beginning of spring training next year.”

Since the injury surfaced as he threw in spring training, LaRoche has tried rehab, taking time off, resting and receiving cortisone shots — but nothing worked. After a meeting with LaRoche and team officials, surgery was determined to be the best solution.

“Everything we tried to do was trying to get Adam out there to try and produce this season,” Douoguih said. “As soon as we recognized that this was something more problematic, through our standard program, we shut him down, put him on anti-inflammatories, we then progress to an injection. We shut him down after that and gradually tried to work him back in after that. Everything we did was gradual, really textbook. Unfortunately, he was just not able to get through that and required surgery.”

During the surgery, Douoguih said he will be able to tell the extent of LaRoche’s injury. If its just a cleanup, LaRoche could be facing a three to four month recovery, Douoguih said. If its a more extensive surgery that requires more repair, the recovery could last between six and seven months.

“It’s disappointing because it negatively affects the bat and takes that Gold Glove caliber defensive first baseman, 25 homers and 100 RBI out of your lineup,” GM Mike Rizzo said of Adam LaRoche’s season-ending injury. (Greg Fiume/GETTY IMAGES)

“It’s been frustrating,” LaRoche said before the announcement. “After I’ve had a couple weeks of taking it easy, I came back and starting hitting and throwing.”

Asked how his injury felt compared to when he first landed on the disabled list, LaRoche said, “probably about the same.”

In January, the Nationals signed LaRoche, 31, to a two-year contract worth $16 million guaranteed, replacing Adam Dunn at first base with a reliable veteran and strong fielder. The injury, however, limited LaRoche at the plate, who managed a .172 batting average before being placed on the disabled list. At first, he insisted his shoulder ailment did not affect his swing but later admitted it drained his hitting strength.

“It’s disappointing because it negatively affects the bat and takes that Gold Glove caliber defensive first baseman, 25 homers and 100 RBIs out of your lineup, which can affect any team,” Rizzo said. “But, you know, again, nobody is feeling sorry for the Washington Nationals. We have to move on. We feel that we had secondary plans in place to fill that void.”

The Nationals have relied solely on Michael Morse to play first base since.