BEIJING (AP) — Three events in and American decathlete Trey Hardee had to withdraw. His throbbing lower back couldn't take anymore punishment.

The two-time world champion hurt his back on Friday in the long jump, then struggled in the shot put before shutting himself down at the world championships. Hardee said he was "devastated" to have to pull out of the 10-event competition, but it "just wasn't meant to be."

"I need to focus now on getting prepared for 2016 and what will be my final Olympic campaign," Hardee said.

After a solid time in the 100-meter race, Hardee was in good shape to push defending champion and teammate Ashton Eaton. But Hardee did something to his lower back in the long jump, clutching at his left side when he stepped out of the pit after a foul on his third attempt.

It carried over to the shot put, where he didn't throw anywhere near his usual distance. His agent, Paul Doyle, didn't know the exact injury or how long this might sideline Hardee.

"He is undergoing testing at the USATF medical office today to determine the extent of the injury," Doyle said in a statement.

Hardee, who lives in Austin, Texas, is no stranger to pain. He was only months removed from surgery to fix a ligament in his elbow when he captured Olympic silver at the London Games, finishing behind Eaton. It was the first time the Americans had gone 1-2 in the Olympic decathlon since Milt Campbell and Rafer Johnson in 1956.

The 31-year-old Hardee's personal-best score is 8,790 points, which he set in Berlin in 2009. He currently ranks behind only Eaton, owner of the world record (9,039 points), Dan O'Brien and Bryan Clay in American history.

Such a big name in the sport, even his two dogs have earned endorsement deals. The Rottweiler mixes, Minka and Luca, actually are sponsored by a pet food company that keeps them rolling in treats.

"My dogs getting a sponsorship out of all this?" Hardee said. "Now that's one of the cooler things that's ever happened to me."