Britain's 2013 Tour de France winner Chris Froome will miss the Tirreno-Adriatico stage race in Italy because of a chest infection.
The Team Sky rider, 29, was due to be part of a field including Spain's Alberto Contador and 2014 Tour de France winner Vincenzo Nibali.
Froome, who won the Ruta del Sol stage race in February, said: "I've been ill for a few days now and, unfortunately, I couldn't shake it off in time."
The seven-day race begins on Wednesday.
Froome said he "should be fine" to race in the Volta a Catalunya, which begins on 23 March.
He added: "After speaking with the doctors we decided as a precaution that it would be best to take a few days off the bike to recover fully.
"This is obviously frustrating after the good start that I've had to the season, but it's a minor setback."
Froome missed last year's Tirreno-Adriatoico with a back injury.