McIlroy, the defending champion, was speaking after his early exit in the Players’ Championship after rounds of 79 and 75 left him 10 shots outside the cut mark on 10-over-par at TPC Sawgrass.
“Probably the swing issues and where it all stems from, probably like October last year, doing a little bit of speed training, started getting sucked into that stuff, swing got flat, long, and too rotational,” said McIlroy after a wayward display in the $15 million event.
“Obviously I added some speed and 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. That's what I'm frustrated with.”
In reply to being asked why he’d gone down that route when he was already one of the longest-hitters in the game, the four-time major winner added: “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, whoa, if this is the way they're going to set golf courses up in the future, it helps. It really helps.
“The one thing that people don't appreciate is how good Bryson is out of the rough. Not only because of how upright he is but because his short irons are longer than standard, so he can get a little more speed through the rough than us, than other guys.
“I thought being able to get some more speed is a good thing, and maybe just to the detriment a little bit of my swing, I got there. But I just need to maybe rein it back in a little bit.”
After a hectic start to his 2021 schedule, the Northern Irishman is hoping some time off will help him get his game sorted for next month’s Masters, where he will be bidding to complete the career grand slam.
“It was certainly ambitious, especially going from Abu Dhabi to the west coast,” he said of starting the year in the Middle East in January then heading straight to California. “But I wanted to play. “I played sparingly sort of from September onwards last year, so I wanted to play quite a bit.
“I think these next three weeks coming up will give me some time to work on some stuff and I can get ready for (Augusta).
“I certainly have an idea in my head of the way I want to play that golf course, and I felt like I really made some good strides in November.
“But, if you're not hitting the shots, then it doesn't make any difference. First and foremost I have to be able to hit the shots and get the ball starting on my line and control the flight and control the spin.
“At the minute I'm struggling to do that, and if you can't do that going to Augusta, you've got no chance.”