Rory McIlroy tweaks left knee at the Memorial Tournament

With the biggest superstar in the history of golf already out indefinitely due to injury, the game is holding its breath on Thursday with Rory McIlroy nursing an apparent knee issue and in noticeable knee discomfort after several shots. Tiger Woods confirmed on Wednesday what everyone already knew, that the 14-time major winner would miss the U.S. Open in two weeks at Pinehurst. Now Tiger’s Nike stablemate is apparently dealing with a knee tweak and struggling to make his way around Muirfield Village during the opening round.

An on-course report from Golf Channel said that McIlroy tweaked his knee during a recent workout, but any sign of that was not apparent until the 7th hole on Thursday. That’s when McIlroy ripped a fairway wood from 254 yards out at the par-5, and the Ulsterman immediately limped, winced, and then worked on his left leg.

Golf Channel commentator Nick Faldo promptly cited all the force he puts on that leading leg just “like Tiger.” It seemed like just a momentary bit of discomfort after a violent shot from a clean fairway lie. But McIlroy clearly protected his knee on subsequent shots, particularly up on the tee where he came out of it a couple times. After he came out of it and sent his drive right at the 10th, Rory hobbled to the back of the tee and worked on the knee yet again.

Losing McIlroy to a WD just four days after the best win of the golf year and two weeks before the U.S. Open would be a blow to the momentum the game hoped to achieve following an awesome Sunday on both sides of the Atlantic.

So far, his game is definitely unaffected as he continues to roll in that area, getting to 5-under through his first 10 holes. He’s one shot off the pace and Golf Channel’s Todd Lewis said he overheard Rory say he planned to continue (kinda hard not to when you’re on pace for the lead). He does have the option of calling for the physio to get some on-course treatment during the round.