Aberdeen boss Derek McInnes today received a triple fitness boost with long-term absentees closing in on a return.
On-loan NAC Breda full-back Greg Leigh is stepping up his rehabilitation from a fractured tibia.
Leigh was today set to undergo a scan on the injury that has ruled him out for two months.
It is anticipated the loan defender will be given the go-ahead to come out of a protective boot.
McInnes also confirmed Craig Bryson has returned to full training after nearly three months out.
Midfielder Bryson has recovered from ankle surgery and is in contention to face Celtic on Sunday.
Attacker Scott Wright has also returned to ball work in training and is on course to return ahead of schedule.
It was initially feared Wright’s season was over due to cruciate ligament surgery but he is on schedule to return in four to six weeks.
McInnes said: “Greg Leigh is reimaged today.
“The train of thought is if the image is clear and good then he comes out of the boot.
“It is probably going to be the end of the month before Greg can be back into proper full training, all being well.
“Craig Bryson, though, is back in full training and trained great.
“Hamilton came too soon for him, but the plan is for him to available for the weekend.
“Scott Wright is progressing well and is back doing some running and some ball work at the minute.
“He is probably about a month to six weeks away which is a bit ahead of schedule.”
Centre-back Ash Taylor is also set to be in contention to return against Celtic having missed the last two games with a tight calf.
After netting in an impressive performance in the 3-1 defeat of Hamilton, striker Curtis Main is expected to retain his place on Sunday.
Leading scorer Sam Cosgrove, on 21 goals for the season, could be relegated to the bench for the second game in succession.
McInnes paid tribute to summer signing Main’s professionalism while waiting for his opportunity to impress.
He said: “Curtis has been bursting to get that chance.
“It is real testament to Curtis that his professionalism allowed him to play 90 minutes as hard as he did.
“He never gave their centre-backs a minute.
“Once Curtis got us up and running with his brilliant goal you could see our confidence in the final third.
“We had plenty of shots, plenty of crosses and we could have scored more.
“We’ve found it difficult against teams sitting in against us.
“For all the possession we’ve had, we weren’t doing enough with it. Against Hamilton the game was a bit more open and we were clinical with our work.
“Now we need to build from that.”
Aberdeen now face the Premiership leaders at Pittodrie on Sunday.
The defending champions’ last visit to the Granite City delivered a 4-0 humiliation for the Reds, with all the goals coming in the first half.
Aberdeen have faced Celtic since then, narrowly losing 2-1 at Parkhead.
McInnes accepts the opening salvos against Glasgow duo Celtic and Rangers (5-0 loss at Ibrox) were unacceptable.
But he is confident the Reds have made moves to change that in recent games against the Premierships top two.
Key to that has been aggression and McInnes will demand his squad deliver on Sunday.
He said: “In the two games we had against the Old Firm earlier in the season we got torn apart and battered.
“We gave away cheap goals.
“The three games since then, the two against Rangers and the game at Celtic Park, have been far closer.
“There has been far more intent to us, and we have been far more aggressive with our work.
“Hopefully that is the Aberdeen team we get on Sunday and it gives us a chance to get a result.”