Defending Tour de France champion Tadej Pogacar lost a third UAE Emirates teammate when his lieutenant Rafal Majka pulled out injured ahead of Wednesday's mountain stage 17 climb to Peyragudes.
Slovenian Pogacar needs to overturn a two minute and 22-second deficit to overall leader Jonas Vingegaard of Jumbo as their cat-and mouse struggle for the yellow jersey enters its end game.
The 2020 and 2021 champion Pogacar has already lost climber George Bennett and flat plains specialist Vegard Stake Laengen, while Vingegaard has also lost two teammates.
"Unfortunately Rafal Majka will not start stage 17... after sustaining a strain injury to his thigh after mechanical trouble on stage 16 when his chain broke," UAE Team Emirates doctor Adrian Rotunno said.
Pogacar was leading the race by 39sec from Vingegaard before losing Bennett and Laengen to positive Covid tests last week and then struggling in the Alps on the Col du Granon on stage 11 in intense heat.
But on stage 15 Denmark's Vingegaard lost two teammates to injury, levelling the playing field as Primoz Roglic pulled out and Steven Kruijswijk fell heavily and was taken away by ambulance.
"If I hadn't lost my teammates I wouldn't be behind now," Pogacar said at the time, and looked confident and strong on stage 16.
Just ahead of the Tour, Matteo Trentin, a key member of Pogacar's team, also withdrew from the race with Covid.