Celtic manager Neil Lennon concedes striker Gary Hooper is likely to depart the club.
The 25-year-old was the subject of several failed bids from Premier League side Norwich City in the January transfer window, and they are reported to be one of several clubs interested in acquiring his services ahead of the new season.
A groin injury has sidelined Hooper during pre-season thus far, and the striker looks certain to miss the first leg of their Uefa Champions League second-round qualifier against Cliftonville on Wednesday.
And, with the former Scunthorpe United man about to enter the final year of his contract, Celtic could decide to sell to avoid losing him on a free transfer next year.
"It will be difficult to convince Gary to stay," Lennon admitted.
"He has not featured much in pre-season and the games start in earnest for us on Wednesday night.
"So he'd have a bit of catching up to do and I don't know where his mind is at the minute.
"Has he played his last game for Celtic? Never say never but it's looking more and more that way."
With Hooper's future in doubt and midfielder Victor Wanyama joining Premier League side Southampton, Lennon is keen to add to his squad.
"I haven't spoken to [chief executive] Peter Lawwell yet about bringing someone in but we need two or three players if we're going to get back into the Champions League," he added.