Daniel Ricciardo has refuted claims that Sebastian Vettel thought of quitting Formula 1 during last year's Championship.
Earlier this week Vettel's former team boss Christian Horner stated that the German, who failed to win a single grand prix in 2014 bringing an end to his run of four successive World titles, considered quitting the sport.
"There was probably a stage last year where he thought about whether he wanted to stop or not, whether he was getting the same level of enjoyment and whether he wanted to continue," Horner said.
"He was just unhappy with the direction F1 had gone in. The previous four years had been so successful for him, with a car that he loved driving, then suddenly things were very different."
Ricciardo, though, has cast doubt over Horner's claims.
"From what I saw he was never going to leave, he's way too passionate about the sport to just walk away," he told Sky Sports News HQ.
The Aussie has also backed Vettel to invigorate Ferrari as the Scuderia look to return to winning ways.
He added: "With Ferrari this year he’s going to have a challenge, but I think he’ll come out of his shell some more and try and get them going again."