Celtic boss Ange Postecoglou has confirmed striker Kyogo Furuhashi is out for "at least three to four weeks" with a knee problem.
The 26-year-old, who has scored seven goals in nine games since signing from Vissel Kobe in July, picked up the injury with Japan and could miss seven games before the next international break.
With strikers Odsonne Edouard and Leigh Griffiths having left the club in the transfer window and new Greek signing Giorgos Giakoumakis still getting up to speed, Postecoglou is set to turn to fringe player Albian Ajeti to lead the line against visitors Ross County in the Premiership on Saturday.
Celtic will be looking to return to winning ways at Parkhead after defeats to AZ Alkmaar and Old Firm rivals Rangers before the international break, but will definitely be without Furuhashi for the clash.
"As everyone is aware he picked up an injury playing with the national team," Postecoglou said.
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"We have got him back and the initial assessment is we are looking at least three to four weeks at this stage which means he will miss the next few games but at the same time, he is pretty optimistic about working hard to get back so we will just have to wait and see.
"It is disappointing, it is disappointing for him because he has obviously had a great start to his Celtic career and it is one of those things.
"We obviously wanted to keep it going and obviously help us as well but we understand it is part of football and these things will happen and we just have to get on with it."
Switzerland international Ajeti has failed to pin down a regular first-team spot since joining Celtic from West Ham on a four-year deal in August 2020 for a reported fee of £5m and has not scored in five appearances off the bench this season.
Postecoglou said: "I have said before I don't go around giving players cuddles but will give them opportunities when it comes and it is up to them.
"To be fair to Albian, he has worked his socks off in training and I know if the opportunity arrives for him tomorrow he has done everything he can to be in a good position to take it and it is up to him. If he starts banging goals in he makes it difficult for other players to take his position."
Postecoglou, who also confirmed midfielder James McCarthy will be available after recovering from a knock but is still without winger James Forrest, reflected ruefully on the challenges he has already had to face in his short time as Parkhead boss.
He said: "You have got to love football. It's great. You have the best laid plans.
"We had challenges at the back in the first period, at full-back and centre-back, and we got through it by the skin of our teeth and now we have cover in all those areas which is great but we are a bit short at the other end.
"That is the challenge football puts up for us but I am still confident we will still be a good team going forward.
"If we can get through this period with Kyogo missing, Georgios getting up and running and without guys like James Forrest and Mikey Johnston, who hasn't played at all, then it will mean we have a stronger conviction about what we are doing moving forward."
Meanwhile, Celtic have been told that no away fans will be allowed to attend their Europa League tie next Thursday against Real Betis, despite being told on Wednesday by the club they would be allowing an away allocation.
Betis say the Spanish local authority has instructed no visiting fans will be allowed to attend the match with Celtic issuing a statement saying they were "extremely disappointed" by the situation and advising fans not to travel to Spain anyway.