Rory McIlroy’s weekend at the Arnold Palmer Invitational never got started as he withdrew Saturday afternoon before his tee time with a back injury.

It’s just the second WD of McIlroy’s PGA Tour career. The first came at the 2013 Honda Classic when he was 7 over and cited a toothache.

According to Golf Channel’s Todd Lewis, the World No. 2 tweaked a muscle in his back during a pre-round gym session. After tweaking his back, McIlroy went to the range to hit some balls and see if he could work through it. He ultimately decided not to play. McIlroy told Lewis he might have been able to gut it out, but didn’t want to push it with the major season on the horizon.

McIlroy released the following statement shortly after his WD.

“While warming up in the gym this morning, I felt a small twinge in my back. As I started hitting balls on the range before the round, it worsened and developed into muscle spasms in my lower back. Unfortunately, I’m not able to continue and have to withdraw. I was excited to compete this weekend. I wish the Arnold Palmer Invitational a great finish and look forward to being back next year.”

McIlroy fired a 4-under 68 on Friday to jump into the top 10, but still entered the weekend nine shots behind 36-hole leader Daniel Berger. He is coming off a T2 finish at the Genesis Invitational in his last start. With the Players and the Masters on the horizon, McIroy arrived at Bay Hill feeling confident in the state of his game.

“It feels like it’s in really good shape,” McIlroy said on Wednesday. “I’m really happy with the signs that I saw at Pebble Beach and Riviera. I think I did really well in Strokes Gained: Approach in those two events. I drove the ball pretty well at Riviera. I just couldn’t make a putt for 27 holes. But I put that down to the sort of the very fast, bumpy poa annua. But I was really happy with where my game was coming out of the West Coast, and I’ve kept ticking along the past week and played some golf and I’m excited for these two weeks, I feel like I’m in good shape.”

The career Grand Slam winner is the defending champion at next week’s Players Championship and at the Masters, which is 33 days away. McIlroy told Golfweek’s Adam Schupak that he was “all good” as he left the Bay Hill property.

McIlroy, who defeated J.J. Spaun in a three-hole playoff at last year’s Players, is scheduled to have his pre-tournament press conference on Wednesday at 7:45 a.m.