Halley Batista of Brazil competes at the U.S. Open of Surfing in Huntington Beach, Calif. (Michael Goulding/AP/The Orange County Register)

America’s most famous surfer, Kelly Slater, will not compete in this year’s U.S. Open of Surfing, which is currently underway in Huntington Beach, California. The reason, according to the Los Angeles Times, is because of an injury.

“Slater has recently re-aggravated an old shoulder injury, forcing him to withdraw from this week’s U.S. Open in hopes of resting up for the Billabong Pro Teahupo’o,” Dave Prodan of the Associate of Surfing Professionals told the L.A. Times.

Slater has not said how he suffered the injury, but some, including The Inertia, have speculated the 42-year-old may have hurt himself while “skurfing,” which, according to the L.A. Times, is surfing while being towed by a boat. Slater posted video of his skurf on Sunday.

Kelly, who is currently the No. 6-ranked men’s surfer in the world, will be missed in the competition, but there are plenty of others to keep an eye on in this breathtaking tournament, including the 2013’s world No. 1 surfer Julian Wilson of Australia. (He’s currently ranked 15th overall this year.) The men’s competition continues today through Sunday.

The U.S. Open also features a women’s tournament, as well as male and female junior tournaments. The junior male rounds got underway on Saturday and will continue on Thursday and Saturday. The junior female rounds began Sunday and will continue Saturday. And the women’s tournament is set to begin Tuesday and continue through Sunday.

The tournament is being streamed online.

Correction: Julian Wilson’s current rank was originally misrepresented.