By this time tomorrow, they will know if his significant contribution to the 4-1 win against Kilmarnock was the striker's latest input to the title charge, or his parting shot before beginning the next phase of his career in England.
Victor Wanyama's influence in Neil Lennon's side appears much more assured, the Kenyan having told journalists in his homeland prior to last night's game that a deal had been reached between his representatives and the club that his departure would be delayed until the summer, at least.
With the closing of the window tonight, the distracting and potentially-destructive influence speculation can bring to the door of any club will no longer be an issue.
For that, Lennon will be very grateful, the manager having expressed his deep dislike for the system which forces him to fire-fight at a stage of the season when he has much more important matters requiring his full attention.
Restoring his side to an even keel after they were so badly rocked by their Scottish Communities League Cup semi-final defeat on Sunday was top of his list of priorities when SPL action resumed.
And the players he had described as 'spoilt kids' behaved the way every errant child does.
Having been rebuked by their guardian, they go out of their way to show they deserve all the love and attention which surrounds them.
There were no petted lips, just a desire to get back into the good books.
Only Lassad Nouioui and Joe Ledley found they had been sent to their room – or, in this case, to the bench.
And, ironically, four minutes before the interval, it was the Welshman who got the recovery mission underway.
Ledley had been on the pitch just a few minutes as a replacement for Emilio Izaguirre – who appeared to pull a hamstring – when he let loose with a 35-yard rocket which flew over Cammy Bell.
Not to be outdone, fellow countryman, Adam Matthews, struck an equally-powerful shot four minutes after the break which again left Bell floundering.
This was all in stark contrast to how clinical Celtic had been in the other scoring opportunities they had created to this point.
They could have been comfortably ahead by the break, but Kris Commons saw two efforts clip the bar and Georgios Samaras was hustled out of a clear scoring opportunity by Mohamadou Sissoko.
That said, Killie – who won on their previous visit to Parkhead in October – believed they should have been the side to take the lead.
Under intense pressure from Ross Barbour, Charlie Mulgrew got into a fankle near his goal line.
Lukasz Zaluska scooped the ball out, but Barbour and his team-mates were convinced it had crossed the line.
The assistant referee, whose view was obscured, stood motionless at the corner flag, and it was referee Calum Murray who made the call, inexplicably awarding Celtic a free-kick some 10 yards from the point of contention.
It was perhaps just as well Killie boss Kenny Shiels was confined to the stand, as he serves his latest ban.
He was certainly much happier when Cillian Sheridan did get the goal which brought Killie level two minutes after the break.
William Gros got the better of Wanyama – moved into defence in the reshuffle after the departure of Izzy then Samaras, who also appeared to damage a thigh – before sending the ball to the former Celt, who rammed his shot into the net from close range.
The fact parity was established for only two minutes before Matthews struck confirmed that the Celtic players had no desire to face another tongue lashing.
Though Killie were given more sights of goal than Lennon would like – Barbour had a rasper of a shot from 25 yards which stung the palms of Zaluska and Jerome Tesselaar sent one dipping over the bar after
getting the better of Wanyama – the overall quality of performance was far superior to that which had been delivered at Hampden.
Had Commons and Hooper, in particular, had their shooting boots on, the margin of victory would have been far wider.
As it was, it was left to Anthony Stokes to come off the bench and get his first of a troubled season – set up by Hooper – to finally take the game beyond Killie with 12 minutes remaining.
Matthews popped up with goal No.4 five minutes later, knocking a cross from Stokes over the line from close range for a rare double for the full-back.
Regaining the winning thread was the objective, and the march towards retaining the SPL title is back on track as Celtic surge 15 points clear.
Now their attention will be turned towards Sunday's William Hill Scottish Cup fifth-round tie at Kirkcaldy against Raith Rovers.
Lennon, like the Celtic fans, will hope a full complement of star players are available for that game, with the window having closed without Hooper, Wanyama or anyone else being allowed to escape.
January has proved to be a testing time for Lennon, and, ultimately, for his players.
February – with the first Champions League last 16 tie against Juventus at its heart – is unlikely to be any less traumatic.