And the 37-year-old American joins 26-year-old Hughes at the top of the leaderboard after the 2016 RSM Classic victor fired a bogey-free round which included five birdies.
"I hit a couple of tee shots practising on Monday and just didn't feel right and I've been getting treatment on it", McIlroy said. I felt like there were a lot of thoughts going in my head, and the first day I was still thinking about the Masters and everything that has been going on, and so it was, like I said earlier, it was important to shoot a decent round.
England's Sam Walker sat four shots off the lead after a third round of 68, with France's Matthieu Pavon another stroke back on 12-under.
Mackenzie Hughes and William McGirt fired identical 67s to take the co-lead after the first round of The Players Championship as Sergio Garcia aced No. 17 in his first event since winning the Masters.
"My back has got a little bit stiff again, I guess just from obviously building it up and playing through and then not doing anything for three weeks and then coming back last weekend and hitting balls for four or five hours a day".
The resulting 71 left McIlroy on one under par overall, with world number one Dustin Johnson two over after a 74 which included five dropped shots in the last six holes.
The 2008 Players Championship victor is playing in his first event since his triumph last month at Augusta National and looked rusty coming out of the gate.
"I was able to hit some really, really quality shots and thanks to that and some great putts, we were able to shoot a very good five-under".
Danny Willett's troubles continued after withdrawing only nine holes into his second round.
Poulter had surged through the field late on the second day as he posted a 67 in the final group of the day, and he was content to grind it out in the tricky conditions and hand in a "boring" scorecard containing one birdie and 17 pars. "But I'm in a good spot for tomorrow, I'll come out tomorrow and see if I can shoot a number". I don't really need to see anyone else to tell me, I've had it many times before. "I felt like my putting was good enough to roll in a few 20-footers if I had to, and I just couldn't get the ball there". Garcia, Patrick Cantlay (72) and Alex Noren (72) were another shot behind.
McGirt is just the 26th player to record two eagles in one round during The Players Championship and just the sixth to do so on the back-nine at TPC Sawgrass. 11 and 16. In four prior starts at TPC Sawgrass, McGirt's only other sub-70 round was a 7-under 65 in the second-round a year ago. "I was able to do that today and try to do more of that the next three days".
"I was really patient".
His popularity might have reached new heights on Saturday when Garcia made a charge up the leaderboard. It marked the 10 year in a row that Garcia was at par or better after the opening two rounds of The Players. It pitched high right and then just spun back in the water. Adam Scott had a one-shot lead when he finished with a pair of double bogeys.