Tiger Woods said his back was tight during the opening round of the Memorial Tournament, though the 14-time major champion stressed there was no pain.

Former world number one Woods - who has been plagued by back issues and surgeries - was wayward early but salvaged his round with an even-par 72 in Dublin, Ohio Thursday.

A five-time champion at Muirfield, Woods struggled early as he bogeyed his second hole before double-bogeying the 15th having hit his tee shot out bounds, while the American dropped another shot at the next hole.

Woods turned in three-over 39 heading to the front nine, however, he rallied by birdieing four of his nine holes to be seven shots behind trio Hideki Matsuyama, Abraham Ancer and Joaquin Niemann.

Reflecting on his round, the 42-year-old said: "I wasn't rotating very well today, back was tight, and just it is what it is some days.

Woods added: "I just have days like that. It's aging and it's surgeries. Just got to make the adjustments.

"I'm able to make them now. Beginning of the year, I wasn't able to make them, because I didn't really know what to do yet. But now you see me making these adjustments on the fly."

"I always will [have tightness]; my back is fused," he continued. "I'd rather have days like this than pain."