Rami Gershon and Tom Rogic – complete with necessary paperwork – are also expected to be in contention for the quarter-final in Kirkcaldy, with the on-loan defender pushing to make his debut against Kilmarnock in tomorrow's SPL game at Parkhead.
James Forrest is also edging towards a comeback after stepping up his training following the hamstring injury which has kept him out since Boxing Day.
And, with Anthony Stokes now pushing for his first start since August after coming on a sub in Celtic's last two games – the 4-0 win over Dundee United and Sunday's shock League Cup semi-final defeat against St Mirren – Neil Lennon's options are increasing as he decides on the line-up he is demanding bounce back from their Hampden horror no-show.
Ambrose was expected to be on international duty for another two weeks as Nigeria were predicted to go all the way in the African Cup of Nations.
But, the Super Eagles have failed to soar in South Africa. They only managed draws in their opening group matches against Burkina Faso and Zambia – with the Celtic defender sent off in the first match for two yellow cards.
If they don't defeat Ethiopia in Rustenburg tonight, they are in serious danger of exiting the competition before the knockout rounds.
That would be good news for Celtic as Ambrose would return to Scotland immediately and step back into his position in the centre of their defence.
Gershon was signed on loan from Standard Liege at the beginning of this window with a view to filling the breach while Ambrose was on international duty and Kelvin Wilson was serving his two-game ban.
However, in his push to build up his fitness, the Israeli international has suffered a couple of strains, which have put his debut on hold.
Lennon is confident the 24-year-old will prove to be an astute acquisition – and soon.
The Hoops boss said: "He is strong, a very good defender and gives us that balance on the left-hand side. He's not played a lot of football and I think there's a real hunger to make his mark.
"I always like those type of players who want to come and prove a point. He has picked up a few niggles since he came in, but it won't be long before you see him in the first team."
Lennon will continue to examine the possibility of adding more players to his squad before the transfer window closes on Thursday night.
As he anticipated, the telephone lines are beginning to get much busier as agents attempt to place players.
But, unless it is someone Lennon believes can improve what he already has, or can strengthen a position which he considers weak, he is not going to bite.
The club are in the market for another keeper to back up Fraser Forster and Lukasz Zaluska, and another short-term loan could be on the cards to fill this gap.
Mo Bangura – who spent the last six months at previous club, AIK – has already been allowed to move out on a similar deal, joining Elfsborg until December.
But Lennon has not given up on the Sierra Leone striker, who will still have 18 months of his contract to run when he returns from Sweden.
The manager told Celtic TV: "He's still our player and we're hoping he will come back even more confident than he did after his last spell there with AIK."