GRINDELWALD, Switzerland, June 14, 2011 – Spanish sprinter Oscar Freire is set to leave the Tour of Switzerland Wednesday in order to undergo surgery on troublesome sinuses, his Rabobank team confirmed.

Freire, a former three-time world road race champion, has suffered from the problem on and off in recent years, making breathing difficult.

He had similar surgery after last year’s Tour de France shortly after quitting the Tour of Italy because of a sinus infeciton.

Freire went on to race the Tour of Spain last September, emerging in top condition to win Paris-Tours at the end of the season.

However the problem re-emerged earlier this season, forcing the 35-year-old Spaniard out of racing the Ghent-Wevelgem semi-classic.

Freire, a former winner of the Tour de France green jersey for the points competition, was not scheduled to race the three-week epic, held July 2-25.

He is scheduled to go under the knife in Spain on Thursday.

Wednesday’s 198.3 km fourth stage from Grindelwald to Huttwil is one of only two stages in the nine-day event that suit non-climbers and sprinters such as Freire.