Rory McIlroy’s bid for a second Players Championship victory suffered a potentially fatal blow as Scottie Scheffler played through the pain barrier to keep his hopes of an historic title defence alive.

McIlroy held a share of the overnight lead following an opening 65 at Sawgrass, but could only add a second round of 73 to slump eight shots behind US Open champion Wyndham Clark.

An erratic start saw McIlroy card three birdies and three bogeys in the first six holes and, after reaching the turn in 35 with a birdie on the ninth, the world number two bogeyed the 12th, birdied the 13th and double-bogeyed the next in a frustrating inward nine of 38.

Scheffler had earlier received treatment from a PGA Tour physio during a second round of 69 which left him six behind Clark, who reached halfway at 14 under par thanks to a second-consecutive 65.

“I hit a shot on my second hole today and I felt a little something in my neck,” Scheffler, who had started from the 10th hole, explained.

“Then I tried to hit my tee shot on 12 and that’s when I could barely get the club back. So I got some treatment, maybe it loosened up a tiny bit, but most of the day I was pretty much labouring to get the club somehow away from me.

“I did what I could to kind of stay in the tournament today and hopefully it’ll loosen up and then I’ll be able to make somewhat normal swings tomorrow.

“The way I was getting around the course, the way my neck was feeling, I didn’t know if I was going to be able to continue playing, so yeah, good fight out there.”

Scheffler, who won the Arnold Palmer Invitational by five shots on Sunday, is bidding to become the first player to successfully defend the Players Championship title in its 50-year history.

Clark made eight birdies – including five in six holes around the turn – to end the day four shots clear of Olympic champion Xander Schauffele and Canada’s Nick Taylor, with Matt Fitzpatrick and Maverick McNealy another stroke back.

“My iron play’s been very solid, I’ve rolled in a handful of putts and then I’ve really been mentally strong so I’d say all of those things are why I’m sitting where I am right now,” Clark said.

England’s Fitzpatrick held the outright lead when he carded his fifth birdie of the day on the third, his 12th hole, to reach 10 under par, only to find the water with his approach from the rough on the next to run up a double bogey.

“I felt the lie was good enough to kind of hack it on to the right side (of the green),” said Fitzpatrick, who birdied his final hole of the day to add a 69 to his opening 66.

“I was aiming at the right bunker, which if you kind of go back there, you realise how far right it was. It just kind of snagged me and went left.

“Otherwise I felt like I did everything well. Just felt like I played solid overall. Made a couple of putts when I needed to, drove the ball well and my approach play was good as well.”

Asked about trailing Clark by five shots, Fitzpatrick added: “Anything can happen over the weekend, there’s still two days, so you never know.

“Another couple of six-under rounds over the weekend and you never know what can happen. So, for me it’s just about trying to stay patient, just keep doing what I’m doing and go from there.”