OMAHA, Neb. (AP) — Peter Jacobsen has withdrawn from the U.S. Senior Open in Omaha, Neb., because of heat-related illness.

Jacobsen was treated by Omaha Fire and Rescue paramedics after he finished nine holes Thursday. The 2004 U.S. Senior Open champion started his round on the 10th hole at Omaha Country Club and shot a 3-over-par 38. He didn’t require additional medical care.

The 59-year-old Jacobsen, who won seven times on the PGA Tour and has two career victories on the Champions Tour, was playing with Barry Lane and Gary Koch. They teed off shortly after 7:30 a.m., when temperatures were in the mid-70s. The high is forecast to be in the mid-80s.