AKRON — Not much surprises Tiger Woods when it comes to golf. What it took to get back to competitive golf after undergoing back surgery earlier this year is another story.

“There’s no comparison between a knee and a back,” Woods said Wednesday from the World Golf Championships-Bridgestone Invitational. “The knee is so much easier to deal with and rehab from than coming back from a back.

“I’ve had Achilles injuries, obviously knee surgeries, but this thing is just way different. It’s way more debilitating than I thought.”

So much so that Woods didn’t know what to expect when he teed it up at Congressional earlier this month after missing more than three months.

He missed the cut but was pleased he was even able to play, calling the week a high point.

Then two weeks ago Royal Liverpool, poor iron play and bad putting led to his highest total score in an Open Championship in his career. It was as surprising as it was disappointing for the 14-time major champion.

In other words, coming back from this latest injury has been more difficult than previous ones for the 38-year-old.

“Everything needed to get a little bit better,” said Woods when asked to assess where his game is after six competitive rounds following the procedure and what was more than three months off. “Just got to get more efficient at what I’m doing. My good shots are still really good. My bad shots need to be in positions where I know I should miss the golf ball instead of places where I have been missing it.”

A return to Firestone, where he has won eight times, including last year, could help.

But it’s not necessarily a litmus test in Woods’ eyes, either.

“I just need to keep progressing,” he said. “This is only my third tournament back from a back surgery. So that’s something that I’ve had to try and keep in mind because I’ve been in these situations before with my previous surgeries. It takes a little bit of time.”

And maybe more time than in the past.