Tejay van Garderen may be forced to miss one of his most important mountain domestiques in the upcoming Tour de France. Visa problems threaten to prevent Darwin Atapuma from lining up at the start in Leeds on Sunday.

A perennial problem in the 2014 season has been the many visa problems that have forced several Colombian riders to miss important races. Now it seems that the problems may prevent Darwin Atapuma from starting the Tour de France on Saturday.

Earlier this year the Colombia team was forced out of the Tour of Turkey as the visa application procedure for the Giro start in Ireland had been delayed and their passports hadn't been returned in time for the Turkish race to start. For a long time, Julian Arredondo's participation in both the Giro and Fleche Wallonne was in doubt and the Trek rider only returned to Europe for the latter race less than 24 hours before the start due to the slow procedure.

Kazakh riders have had problems too as Maxim Iglinskiy and Alexey Lutsenko both missed the Giro by virtue of administrative problems.

The reason for the Giro troubles was the fact that the race started in Ireland. With the Tour de France starting in England, teams have had similar problems getting the visas required for their participation but due to the limited number of Colombians, there have been fewer conflicts this time around. In fact, Janier Acevedo, Jose Serpa and Darwin Atapuma are the only Colombian riders on the provisional start list.

Unfortunately, the latter may be forced to miss the event. El Mundo Ciclistico reports that there is a big risk that visa problems will preventing him from lining up in Leeds on Saturday.

If Atapuma is out of the race, it will be a huge blow for Tejay van Garderen. The Colombian was signed from the Colombia team as a key domestique for the American in the mountains.