Celtic manager Martin O'Neill has admitted a return for Kyogo Furuhashi is "unlikely" as the striker wants to prove himself at Birmingham City.
The Scottish champions are still looking for an adequate replacement for the Japan international, 12 months on from his move to Rennes.
The 30-year-old struggled for game time in France and has encountered a crisis of confidence in front of goal since switching to Birmingham, netting just once in 25 appearances.
But he appears to have passed on the offer to return on a loan basis to Celtic, where he scored 85 goals in 165 appearances.
When asked about the prospect of a return for the forward, O'Neill said: "I would have said that would probably be unlikely.
"I think there is a viewpoint that he wants to really prove himself at Birmingham, which is no surprise."
Celtic have also been linked with a move for 22-year-old Canada and Hajduk Split midfielder Niko Sigur.
And 20-year-old Ivorian winger Jocelin Ta Bi has been quoted as saying he is on his way to Celtic from Israeli club Maccabi Netanya.
O'Neill could not confirm that any signings were imminent.
"Doing plenty of work on it, seriously and I know that's a big generalisation," he said ahead of his first match back in the dugout against Dundee United on Saturday.
"We are doing that and hopefully try and get a few players in. But there's a lot of work going on at the moment. We are well aware that we have to supplement the squad."
Meanwhile, Dundee United manager Jim Goodwin, who had first-hand experience of O'Neill at his peak as Celtic boss, said he still considers him a force.
The Waterford native was trying to make his way in the game as a Celtic youngster in 2000 when the former Leicester boss joined the Parkhead club for the first time, but the former Republic of Ireland international never made the grade and left for Stockport County two years later.
Goodwin's side beat Celtic 2-1 at Tannadice in December, but he is expecting a different challenge at Parkhead on Saturday.
He said: "It was bizarre kind of circumstances when Martin came in to be caretaker and then Celtic obviously bringing (Wilfried) Nancy in and then so soon after, Martin is back in again until the end of the season.
"So it’s a strange one, but he showed what he could do previously this season (won seven out of eight games). Really good, experience manager.
"I was at Celtic at the time as a kid. I had done a pre-season tour with them in Denmark.
"But Martin soon figured out that I wasn’t quite up to the level and very quickly put me back with the reserves where I spent the next couple of years.
"But I know what he means to the Celtic supporters, what his legacy is at the club and I’m sure the Celtic fans will be delighted to have him back in.
"I’ve obviously listened and watched a lot of Martin on the telly and radio over the last number of years, and he was the manager of the Republic as well.
"He’s had jobs here and there, but I don’t suppose he would’ve expected to get the call from Celtic this season to come back in.
"People talk about the modern day game, I don’t think the game has changed in terms of someone’s knowledge of the game, whether Martin is 73 or 43, I don’t think it makes too much of a difference.
"He knows what it means to win games of football. He knows how to do it.
"We have to hope that we can go there and put on the type of performance that we did here, only a few weeks ago albeit against what we expect is going to be a different system and different personnel.
"We know how difficult a trip to Celtic Park is. History would tell you how difficult it’s been for us to get a result there.
"But we have to be confident, we have to give a good account of ourselves first and foremost, and we have to believe that we can upset the party, so to say."
