A back injury has forced Chris Froome to withdraw from the upcoming Tirreno-Adriatico, with Richie Porte moving from Team Sky's Paris-Nice line-up to replace the Tour de France winner.
The switch around for the British squad was forced by a joint inflammation in Froome's lower back, with the knock-on effect also impacting the team's challenge at Paris-Nice, starting on Sunday.
Despite pulling out of the Italian stage race, the back issue is not thought to be a long-term issue, with Froome expected to be back in action by the end of the month.
"Chris has suffered a slight inflammation to the sacroiliac joint in the lower back," confirmed Team Sky doctor Alan Farrell. "As a precaution we have chosen to withdraw him from next week's Tirreno-Adriatico so he can focus on recovering and preparing for the Volta a Catalunya."
In a statement on the team's website Rod Ellingworth, Team Sky's performance manager, added: "This is just a minor setback for Chris and we hope he will get back to full training within a week. He is obviously disappointed to miss Tirreno-Adriatico but we shouldn't take any chances at this stage of the season."
Froome's chief helper at the Tour de France, Porte will now turn his attentions to Tirreno-Adriatico, which begins on March 12, passing up the chance to defend his 2013 title in the "Race to the Sun".
Geraint Thomas is now set to be handed a big opportunity with a leadership role at Paris-Nice, while fellow Briton Ben Swift gets a late call-up to Saturday's Strade Bianche.
Sir Bradley Wiggins will now no longer ride the weekend's one-day event, but is still set to line up alongside Porte at Tirreno-Adriatico on Wednesday.