Celtic and Leeds United are both said to be interested in signing Matty Taylor from Bristol Rovers.
Taylor’s contract at Bristol Rovers expired at the start of the month, and although he has been offered new terms by the Gas, Clarke feels that the striker has decided to move on.
Leeds United and Celtic are believed to be keen to offer Taylor a deal, according to the Daily Mirror.
And Clarke said: "I was never under the impression that we were going to do anything other than lose Matty at the end of the season.
”I haven't changed my thoughts on that, but what I will say is that the door is still open for him.
"I told Matty that when I spoke to him, but I also said that I don't know how long that window will remain. Things change quickly in football and we will have to see how the situation develops over the next few days.”
Leeds and Celtic reportedly scouted Taylor last season, when he was the top scorer in League Two.
Taylor netted 28 goals last season, as Rovers earned promotion into League One.
The 26-year-old is believed to have offers from a host of clubs, who all believe he has the potential to score goals at a higher level.
Celtic have already brought Moussa Dembele in to Parkhead to strengthen their strike force, as Brendan Rodgers seeks further additions to increase his side’s firepower.
Leeds, meanwhile, have signed Marcus Antonsson, but could still look to add another front man before the window closes.