LOUISVILLE, Ky. — Joe LaCava walked nearly every blade of grass on the 18th green at Valhalla Golf Club, jotting notes in his yardage book after stepping off the distances from every edge of the green to every possible pin position. It was just like any other Monday at a major.

The caddie just didn’t know whether any of this information would be useful in the PGA Championship. LaCava was awaiting word on whether his boss — Tiger Woods — would be healthy enough to play the year’s final major.

“I’m optimistic,” LaCava said. “I’m hoping he plays. So I’m just doing whatever work I would normally do.”

The caddie was at Valhalla. So was his car, a silver SUV parked in the spot assigned to the four-time PGA champion.

As for Woods?

Stay tuned. His agent, Mark Steinberg at Excel Sports Management, said in an email that Monday was too early for doctors to decide whether Woods could or even should try to play this week after another back injury.

Woods took another turn toward an uncertain future when he withdrew after eight holes and one final shot Sunday at the Bridgestone Invitational. Before leaving Firestone, he said he jarred his back when he hopped into a deep bunker after playing a shot on the par-5 second hole from an awkward lie off the slope above the sand.

“It’s just the whole lower back,” Woods said. “I don’t know what happened.”

Making the picture even bleaker was the timing. Woods had back surgery March 31 to alleviate the pain from a pinched nerve. The Bridgestone Invitational was only his third tournament since returning from a three-month absence.

And there he went again, riding off the golf course in a cart, struggling to even remove his shoes before LaCava drove him to the airport for a flight back to Florida for evaluation.

“Obviously, I feel bad for him,” Rory McIlroy said Monday. “The game of golf really needs Tiger. He’s had a few withdrawals the past couple of years. I think the first thing is just to get fit and 100 percent healthy, even if that means taking the year off and coming back next year ready to play golf.”