Image 1 of 4 Chris Horner (RadioShack) (Image credit: Bettini Photo) Image 2 of 4 Christopher Horner (RadioShack - Leopard) (Image credit: Bettini Photo) Image 3 of 4 Chris Horner (RadioShack) looked back to his best (Image credit: Bettini Photo) Image 4 of 4 Chris Horner (RadioShack) rode a smart race (Image credit: Bettini Photo)

Chris Horner (RadioShack Leopard) was unable to start the second stage at the Volta Ciclista a Catalunya after a troubling knee issue sustained during Tirreno-Adriatico flared-up. The veteran American finished sixth-overall at the Italian WorldTour event despite suffering pain during his first outing for the 2013 season and will now look to have the injury assessed before returning to competition.

"Already after Tirreno he [Horner] had some knee pain," explained team director José Azevedo to radioshackleopardtrek.com.

"Yesterday in Stage 1 everything went well in the first part of the stage, but in the final the pain started all over again. This morning he even had difficulty walking. Tomorrow Chris will have his knee examined in the hospital in Basel (Switzerland)," he added.

The team was hit by more bad news following the report RadioShack would be ending its sponsorship after young Kiwi George Bennett crashed after 90 kilometres of racing on Stage 2. A number of riders fell on top of the second-year professional and while he was able to finish the 160.7km stage, he incurred damage to the right side of his body which will no doubt impact his performance in the coming days.

"Bennett was involved in a crash in the middle of the peloton around kilometer 90," read a team statement. "George had many riders land on him and suffers from injuries on his right side. George could finish the stage and hopes to be able to start tomorrow in a tough stage with mountaintop finish."

Stage 3 at Catalunya features a grueling ascent to the finish in the Pyrenees with the riders tackling a 180.1km route to the ski resort of Vallter. The final 12 kilometres averages nearly eight percent and with sections over 12 percent, Bennett will hope to have recovered sufficiently for the day.

The 22-year-old is currently the team's best placed rider and will start Stage 3 in 36th however, both Tiago Machado and Haimar Zubeldia lie on the same time as Bennett, 48-seconds behind race leader Gianni Meersman (Omega Pharma - Quick-Step) and will be more likely to be the team's best hopes for a result.