Gorka Izagirre did not start Wednesday's individual time trial and has consequently abandoned the Tour de France.
The eldest of the brothers, a veteran of three Tours, has been struggling with a fever and flu-like symptoms for days, and opted out of taking on the 32km ITT from Embrun to Chorges.
"It's so hard to leave the Tour, but it's a very hard race. I couldn't keep going like this", he told the team's official website. "I've had two very bad days, with a fever, suffering a lot... I had hoped to turn it around and recover, but the Tour is unforgiving.
"I think the best thing is to stop and recover - I couldn't have done much in this state anyway. It's tough to abandon, but it's also hard to keep riding without being able to help the team".
With Izagirre posting a DNF, the team is down to eight riders.