Ross Brawn says a decision about Michael Schumacher's future in Formula 1 will be a tough one, as it awaits a final decision from Lewis Hamilton about his plans.
Hamilton is currently weighing up offers he has from Mercedes and McLaren, with both outfits now believed to be offering the same wages in a bid to win his services.
His final decision will have an impact on Schumacher's future, because if Hamilton elects to join Mercedes it will leave no space for the seven-time champion.
Brawn concedes that the situation is far from settled, and suggests the team is still aware of the benefits Schumacher brings despite his embarrassing exit from last weekend's Singapore Grand Prix.
Speaking about Schumacher's future on BBC Radio 5 Live on Thursday, Brawn said: "It's still under discussion, I'm afraid. I can't comment very much on that, but Michael's been a huge asset to the team, he's really taken us forward.
"I do think Michael contributes an awful lot, so I think the decision for Michael to stay or not continue is a difficult one. Obviously he's very involved in that decision, and discussions are ongoing at the moment."
Brawn said that it was possible a decision about who lines up alongside Nico Rosberg may not be made for some time, as he all but confirmed for the first time that the outfit was interested in Hamilton.
"I think any ambitious team looks at the top drivers and we're an ambitious team, but I think there's an awful lot of speculation," he said. "We will have some things to say in the next few weeks, next few months, and then all will become clear."