Rory McIlroy does not like his shot on 13th tee. Icon Sportswire

Rory McIlroy opened the Tour Championship with an even-par 70 and proclaimed he was “over the moon” with that result, considering his lower back was seizing up for a couple of days. On Friday, he was three shots better with a 67 at East Lake and, remarkably, finds himself only six shots off the pace set by Colin Morikawa and Viktor Hovland with 36 holes remaining in a sprint for $18 million.

“I’m here grinding away, battling away,” McIlroy said following a round in which he suffered only one bogey while being limited to only a certain number of shots he can execute.

The Ulsterman had a spot-on explanation for what’s happening.

“I can’t hit the ball left-to-right; I can’t swing my irons the way I want to,” McIlroy said. “I can’t turn my right side through the ball. So from the top of the swing, I’m just sort of throwing my arms at it and it’s a lot of face rotation and I can only really hit it one way with the irons.

“I can’t hit the driver the way I usually do. Like, teeing it up I’m teeing it down and just hitting a sort of flat little runner down there. A little limited to the shots that I can hit, but I’m getting by.”

McIlroy is disappointed with the timing of the spasms, but he had a telling answer about suffering through this now rather than when he’s prepping for the Ryder Cup near Rome that is set for September 29-October 1.

“I would rather it pop up now than in three or four weeks’ time,” he said. “… Not great timing, but it could be worse as well.”

McIlroy said he hasn’t considered withdrawing from the Tour Championship, nor does he think he can do further damage to his back. Though there are tricky concerns beyond that.

“I wouldn’t say physical,” he said. “I would say maybe bad habits. … Hopefully it starts to feel better and maybe by the end of next week I’ll be able to hit some balls again and get out of those bad habits.”

McIlroy’s current plans are to take just one week off after the Tour Championship before competing in two DP World Tour events — the Irish open and BMW PGA Championship. Then he’ll have two more weeks off before the Ryder Cup.