David Coulthard believes Formula One world champion Jenson Button could struggle in the wake of McLaren team-mate Lewis Hamilton this season.
Button's lap times were slower in testing this week in Valencia, where he complained about the seat in the new McLaren following his move from Brawn at the end of last season.
Coulthard, who recorded 13 Grand Prix wins in his 15 years in the sport, believes it could be a recurring theme when the new season begins in Bahrain in March.
Coulthard said: "McLaren will supply equal opportunity in terms of machinery. Whether they can make both drivers feel equally loved is more difficult for them to achieve.
"If Jenson can match the pace of Lewis there won't be a problem. If Jenson is struggling by half a tenth (of a second), psychologically that is him losing. He will be on a downward spiral where he'll start searching for support in the team.
"McLaren might struggle to pick him up out of that. If McLaren have a winning car, then both cars can't win. If Lewis is getting across the line first then they are not going to be bothered. They are not going to devalue Lewis' performance to enhance Jenson's."
Coulthard, however, applauded Button's decision to take on the challenge.
He said: "Jenson's gone there and put his balls on the line, because he could have stayed comfortably at Brawn and rode out a championship year.
"He was part of the furniture. Now already he has had difficulty getting his seat right in practice. These are housekeeping-type things which he has not had to think about for the last five years.
"Suddenly he is using time and energy getting used to systems where Lewis is just thinking about how quickly can I get through this next corner.
"Jenson's coming from further behind so I would expect Lewis to have the upper hand in the early part of the year. But it's a great chance for Jenson to show he is a great driver and worthy of being world champion.
"It's debatable whether it's the right move but we should thank him for it because it gives us a great story."
Coulthard, an expert commentator for BBC's coverage again this season, also insisted Michael Schumacher's return to the sport with Mercedes makes the coming season the most eagerly anticipated for years.
Coulthard said: "If he comes back and doesn't win a Grand Prix it doesn't take away from his seven world championships. He's giving himself the chance to further enhance his reputation.
"I don't think it's like a boxer who can end up curled up in the corner dribbling and looking a bit punch drunk. He's always got the waiver that the car wasn't quite good enough. It is not as big a risk as other sporting comebacks.
"He might not need the money but life is expensive, especially when you're operating yachts and helicopters and those sort of things.
"Maybe life bores him. It's the buzz, the adrenalin. I didn't achieve anything like Michael did and I wasn't as good a driver, but I miss the adrenalin of going to the grid."