It appears Carlos Sainz jr's quest for the vacant Toro Rosso seat for 2015 may stumble at the sponsorship hurdle.

Although a prominent Red Bull junior and the newly-crowned Formula Renault 3.5 champion, Spain's Marca reports that the 20-year-old's future may depend on Cepsa.

Cepsa is a Spanish oil company and mutual sponsor of the Toro Rosso team and Sainz. Marca reports that Cepsa and the Faenza-based team, however, are on the verge of a split.

"Maybe I need more than results," Sainz is quoted as saying.