The former world No.1 golfer withdrew from the upcoming Northern Trust tournament at TPC Boston, Massachusetts, citing persistent hip and knee problems. The Northern Trust is the first leg of the FedEx Cup playoffs — the culmination of the PGA Tour — and only the top 70 players qualify for the next stage. So, with Koepka currently sitting 97th in the standings, his 2020 season is over. After finishing 2019 ranked as the best player in the world, Koepka’s play has been hampered by injuries, and he has slipped to world No.7. The 30-year-old injured his left knee last year but after undergoing a stem cell procedure on the injury, he further aggravated it just two tournaments later when he slipped on wet concrete, forcing him to retire from the 2019 CJ Cup. He missed three months of golf as a result.Read MoreREAD: Why record-breaking drives could change golf as we know itKoepka receives treatment on day two of the 2020 PGA Championship.In the 13 events he has played this season, he has finished in the top 10 just twice, with his highest finish coming at the World Golf Championships-FedEx St. Jude Invitational earlier this month where he finished tied in second place. In his search for a historic PGA Championship three-peat earlier this month, Koepka had a promising opening three rounds, sitting just two shots off the lead before fading on the final day. But even during the major, he required treatment from a medical assistant. “My body’s nowhere near 100 percent,” Koepka said when he missed the cut at the Wyndham Championship last week.Visit CNN.com/sport for more news, features, and videosThe 2020-21 PGA Tour season begins on September 10 at the Safeway Open in California, and, according to ESPN, Koepka still plans to play at the U.S. Open which starts on September 17 at Winged Foot Golf Club in New York.