American Brandt Snedeker, a three-times winner on the PGA Tour, withdrew from the U.S. Open on Monday because of a rib injury.
The 31-year-old Snedeker, who clinched his most recent title on the U.S. circuit at the Farmers Insurance Open in January, will be replaced in the 156-strong field by American amateur Jordan Spieth.
A twice former U.S. junior amateur champion, Spieth will tee off with compatriots Bill Haas and Nick Watney in Thursday's opening round at Olympic Club.
(Reporting by Mark Lamport-Stokes in San Francisco; Editing by Frank Pingue)