Ian Poulter has pulled out of this week's Honda Classic PGA Tour event after contracting pneumonia.
Poulter, who had complained of suffering from a high temperature, was due to play with compatriot Lee Westwood and Tiger Woods in the first round.
"Sorry guys never been so disappointed in pulling out of a tournament," Poulter wrote on his Twitter account. "Never felt so rough, hope the first reserve plays well in a great group today."
Poulter was replaced by Miguel Angel Carballo, organisers said, but the Argentine could only shoot a nine-over-par 79.
Later, after being examined, Poulter tweeted: "Just been for a chest X-ray. Got Pneumonia guys, rest time for me."
American Davis Love III grabbed a two shot lead after shooting a six-under 64 in Thursday's first round.