It is possible last year's defeat to teammate Sebastian Vettel damaged Mark Webber psychologically, according to the Australian driver's former Red Bull teammate David Coulthard.
Coulthard, now a British television pundit, is referring to last year's Abu Dhabi finale, where Vettel emerged as the underdog to beat favourites Webber and Fernando Alonso to the title.
"Mark was just about to win the world championship," recalled Coulthard, speaking on Austrian Servus TV.
"Since then Sebastian did everything right, which may have impaired Mark's performance," he said.
"It's a bit like with Hamilton or Massa; if you have such a strong teammate, then psychologically it becomes even more difficult.
"The brain controls the body, not the other way around," added Coulthard.
He said Webber, 35, has a lot of thinking to do over the forthcoming winter period.
"Is it how he works with the engineers? Is it something else?
"It's not in the gym because they are both very fit. For Mark it makes sense to try a new approach for next year."