Vuelta debutant Sam Oomen abandoned during Saturday's stage 14, while Chad Haga and Sören Kragh Andersen were the last two riders to finish, trailing in more than five minutes behind the grupetto.
"Sören was very bad," team director Arthur van Dongen told telesport.nl. "Chad was not good either, but hopefully he will get through. It would not be best if we lost more guys."
The team sent Warren Barguil home early on, and Lennerd Hofstede abandoned on stage 12. With Oomen gone, that leaves a team of only six, with the possibility of also losing Andersen and Haga. In addition to Kelderman, the team still has Johannes Fröhlinger, Chris Hamilton, and Lennerd Kamna apparently healthy.
Sunweb is not the only team having problems. Dimension Data has been the hardest hit, and hopes that its remaining three riders will stay healthy until Madrid. Van Dongen said that he understood that Bora and LottoNL-Jumbo are also having problems. Bora has already lost two riders and the Dutch team one rider.