Martin Kaymer has said that it would be a "shame" if Tiger Woods were unable to compete in the US PGA Championship due to injury.

The 14-time Major winner was forced to withdraw from the WGC-Bridgestone Invitational during the final round on Sunday having injured his back on the ninth hole.

The incident came just a matter of months after the 38-year-old had undergone surgery on his back, and it appears unlikely that he will recover in time for Valhalla.

"Obviously everybody wants him to be back at golf tournaments. If you win a big tournament without Tiger in the field you still feel very happy about it, but you want to play against him and it's nice if he's part of every tournament," Kaymer told reporters.

"He brings a lot of people into it. It has a different flair. When Tiger's playing in a golf tournament there's more entertainment and more people. It's such a shame that he had to pull out last week and I hope, and everybody hopes, that he will come back and play this week. On the other hand, I don't know how bad his injury is.

"It's tough to say. If I had injuries like this, I would probably make really, really sure that I'm healthy, because he's 38 years old, so hopefully he will have another 10, 15 years of competing against the guys on the PGA Tour and that he reaches his goal of 18 majors or maybe 19."

Woods has won the US PGA Championship four times in his career.