Brooks Koepka’s season has come to an end.

Koepka withdrew from the Northern Trust on Wednesday morning, the first event in the FedEx Cup playoffs, due to what the PGA Tour said is a knee injury.

He came into the event at TPC Boston ranked 97th in the standings and needed to climb inside the top 70 to advance to next week’s BMW Championship. That would have likely required a top 15 finish. This week’s tournament would have marked his seventh consecutive week of playing.

Last week, after missing the cut at the Wyndham Championship, the four-time major winner said his issue was not the left knee he’s had two procedures on in the past year. However, he admitted that there is a problem that prevents him from getting onto his left side in his swing.

"This is physical," Koepka said after his second round. "I know how to do it; I can do it. I just physically can't do it."

During the PGA Championship, he received several mid-round stretches from his trainer, saying that it was an issue with his hip, specifically citing the tensor facia latae.

Since the restart in June, Koepka has had an up-and-down run, with three missed cuts and two top-10 finishes. He tied for second at the World Golf Championship FedEx St. Jude Invitational and then, after three rounds, played himself into contention at the PGA Championship where he was the two-time defending champion. He faltered on Sunday after a 74 and finished tied for 29th.

He was also in the middle of several controversies in recent weeks for calling out other golfers, such as Dustin Johnson, at the PGA Championship.

There is no word on when Koepka will return however the U.S. Open is in four weeks and he’s finished first, first and second in the past three editions of that championship.