AFC Bournemouth and United States men’s national team midfielder Tyler Adams is looking at yet another lengthy spell on the sideline after undergoing back surgery, according to Cherries manager Andoni Iraola.

Bournemouth are scheduled to play EFL League One side Wrexham at UC Santa Barbara in a preseason friendly on Saturday. Iraola was asked during the pregame news conference about how important it was for Adams to stay fit, at which point he revealed that the midfielder had undergone back surgery.

“He finished the season with an injury in his back,” Iraola said. “He wanted to play Copa América because it was very important for him, but he had restrictions and was still in pain, so two days after they were knocked out, he had surgery.”

Iraola added that he expects Adams to be out for some time, though he declined to mention a specific timeline for the midfielder’s return.

“It is difficult to say how long but he won’t be fit for the start of the season,” Iraola said. “But September? October? I don’t know.”

Iraola was then asked why Bournemouth did not prevent Adams from playing in the Copa América. The manager said, “It was not our choice. It is a decision for the nations, who are allowed to select players, and he wanted to play thinking the injury would get better, but he felt it was getting worse.”

Adams had been on a minutes restriction in the run-up to the Copa América. He didn’t play at all in the 5-1 friendly defeat to Colombia, and went just 14 minutes in the 1-1 draw against Brazil.

In an interview with ESPN in June, prior to the Brazil friendly, Adams was asked about the back injury. He admitted it was an issue toward the end of the club season, but said he was building up his fitness with the U.S.

“It was my back at the end of the season,” Adams said. “But I felt good coming into camp and ready to train, but they were like, ‘No, no, no, let’s just build it up properly.’ Because again, the most important thing for me is obviously to have a good Copa America, but to get into preseason ready to go. I just want to get in a fit place where I can have an eight-, nine-, 10-week buildup into the start of the season and be in a really good place to become robust again.”

Adams went on to play 180 minutes over three matches in the Copa América, including a 90-minute stint in the group stage finale against Uruguay, a 1-0 defeat that knocked the U.S. out of the tournament.

The surgery is the latest injury setback Adams has suffered since completing a $25 million transfer from Leeds United last August. The USMNT captain made just four first-team appearances for the Cherries last season, totaling 138 minutes, after having surgery to repair his right hamstring in October. He had previously undergone a similar procedure while still with Leeds.

The latest operation makes it likely that Adams will miss a pair of U.S. friendlies against Canada and New Zealand in the September international window, which could mark the debut of the next USMNT manager following the firing of Gregg Berhalter on July 10.