Rory McIlroy nightmare at Players Championship with his worst score since 2013 - in pictures

Four-time major winner ten over par and certain to miss cut in Florida

Rory McIlroy after hitting his ball into a bunker on the ninth hole during the second round of The Players Championship in Ponte Vedra Beach, Florida. EPA

McIlroy hits out of a bunker on the ninth. EPA

McIlroy looks for his ball on the tenth hole. AFP

McIlroy of Northern Ireland plays his shot from the 17th tee. AFP

McIlroy plays a shot on the 18th hole. AFP

Sergio Garcia and Rory McIlroy of Northern Ireland on the 18th green. AFP

Lee Westwood, leader after the second round, plays his shot from the sixth tee. USA Today

Defending champion Rory McIlroy's nightmare at the Players Championship continued on Friday, with the Northern Irishman certain to miss the cut after shooting a second-round 75 that dropped him to 10-over par.

The four-times major champion followed up his opening round 79 at TPC Sawgrass in Ponte Vedra Beach, Florida with another poor showing as he shot three bogeys and a double bogey en route to his worst 36-hole score since 2013.

The Northern Irishman, the first defending champion to miss the cut since Rickie Fowler in 2016, said his bid to add speed and power to his game, inspired by Bryson DeChambeau's US Open triumph, had backfired.

"I added some speed and I am hitting the ball longer, but what that did to my swing as a whole probably wasn't a good thing, so I'm sort of fighting to get back out of that," he said.

"I'd be lying if I said it wasn't anything to do with what Bryson did at the US Open. I think a lot of people saw that and were like, if this is the way they're going to set golf courses up in the future, it helps. It really helps.

"I thought being able to get some more speed is a good thing, and maybe to the detriment of my swing, I got there, but I just need to maybe rein it back in a little bit."

The cut will be made official on Saturday after the completion of the second round, which was paused due to fading light. It is projected at even par.

England's Lee Westwood compiled a bogey-free six-under 66 to take the halfway lead on nine under, one ahead of compatriot Matt Fitzpatrick.