Juventus would like Carlos Tevez to make up his mind on his 15-16 plans amid interest from Atletico Madrid.
Tevez has already told Juve that he will not be extending his contract beyond 2016, when he plans to return to Argentina to play for his hometown club Boca Juniors.
Diego Simeone said on Wednesday he was "excited" about the prospect of coaching Tevez next season, while Juve are pressing him to make up his mind.
"The possibility of him leaving is still very high, but I don't want to put a percentage on it," said Marotta told reporters at the club's museum on Wednesday.
"He's a champion; a professional to whom we owe a lot, but we don't have time. We need to move quickly. We're awaiting his answer imminently."