Borussia Dortmund coach Peter Bosz has admitted that he "cannot say" striker Pierre-Emerick Aubameyang will still be at the club following the end of this summer's transfer window.
The prolific Gabonese forward has been strongly linked with a move to Chelsea, with rumours of a £65m deal growing increasingly frequent.
Bosz, who replaced Thomas Tuchel following his exit at the end of last season, has expressed his hope of keeping Aubameyang, but conceded that it is beginning to look unlikely that he will still be a Dortmund player next season.
"There is speculation about it and there will be until the end of August, it is clear," Bosz said, quoted by Football.London.
"For me, what matters is that he is here and that he is fit. He is an incredible player, and as a coach I want him to stay, but honestly, I can not say it.
"We talk to him every day, I talk to Michael Zorc every day, but everything can happen and go quickly in football.
"Last year, I told Ajax that Arkadiusz Milik has to stay, and then he was in Naples."
Dortmund sporting director Michael Zorc, meanwhile, has insisted that the club expect Aubameyang to stay beyond the summer.
"For now, we assume that Aubameyang will stay," he said. "We arranged with him that we are open for talks but only until a certain point of time."