Despite remaining unbeaten in the Scottish Premiership, sections of the Celtic support have questioned the club's signing policy.
The strategy in place has proved fruitful over the last few years: buy young, talented players from somewhat unfashionable leagues, develop them in the first-team and provide them with European experience, before selling them on for a profit.
It worked to perfection during the summer transfer window, particularly with the sale of Victor Wanyama to Southampton. Plucked from Belgian side Beerschot for just £900,000 in July 2011, he departed two years later for a record £12 million fee.
Nevertheless, since their lacklustre campaign in this season's Champions League, Hoops fans have questioned whether the ratio of saving to spending off the back of the current transfer strategy is correct.
Included in that debate is the lack of signings Celtic make from inside Scotland—the summer 2010 procurements of Anthony Stokes from Hibernian and Charlie Mulgrew from Aberdeen being the last time the club looked domestically for reinforcements.
Here, we take a look at five Scotland-based players Celtic could look at in January, with the positions of left-back, left wing and striker of particular interest.
This season: 17 goals, two assists (19 games)
Market value (TransferMarkt.com): £525,000
In the course of just this calendar year, Billy McKay has hit the net 26 times in 38 games for Inverness.
That's double that of current Celtic forward Anthony Stokes (the only striker who's been at the club for the whole calendar year), who has 13 in 46.
But would the Caley Thistle front man really be an upgrade on what Neil Lennon currently has at his disposal?
Well, domestically at least, the Northern Ireland international has the edge in terms of goals over the past two years.
However, Stokes makes up for his poorer goalscoring record this year with his ability to drop deep and create as many as he scores—something McKay doesn't have in his make-up.
He is something Celtic have lacked up front this season, though: a consistent source of goals.
Position: Left winger
Previous permanent club(s): Liverpool, Airdrie Utd
This season: seven goals, four assists (18 games)
Market value: £525,000
Since Kris Commons moved from left midfield to a more central role, Celtic have struggled to consistently fill the left wing position.
Georgios Samaras excels there, from time to time, but that usually comes in Europe and brings with it a more direct style which doesn't suit the Hoops in the Scottish Premiership, where opposition teams are more likely to sit behind the ball and soak up pressure.
Gary Mackay-Steven has neither the goalscoring prowess of Commons nor the powerful style of Samaras, but he would provide a different option to both with his dribbling ability.
That being said, the summer signing of Derk Boerrigter from Ajax almost certainly negates any possibility of procuring another winger. But the Dutchman is yet to find consistent good form and Mackay-Steven in the Hoops is a prospect which would excite many a fan.
Previous permanent club(s): Montrose
This season: zero goals, three assists (20 games)
Market value: £250,000
Celtic have already been linked with a move for Partick Thistle left-back Aaron Taylor-Sinclair, but it's hard to see him as anything other than back-up to Emilio Izaguirre.
Finding cover for the Honduran is one of the areas the Hoops should be looking to strengthen in January. Adam Matthews has had to step in for major matches against Barcelona over the past year, while Charlie Mulgrew and Joe Ledley can both play there, but the team's overall play generally suffers when either are played out of position.
Taylor-Sinclair fits the bill: he is young, and as his contract expires at the end of the season, wouldn't cost much.
The latest figure being talked about is a cut-price £75,000 to land him in January. The Jags will likely accept this rather than face losing him for nothing in the summer, but the 22-year-old faces an uphill battle for regular first-team action should he make the move to Parkhead.
Position: Attacking midfielder/Winger
Previous permanent club(s): None
This season: seven goals, 10 assists (20 games)
Market value: £175,000 (actual asking price £6 million)
The player everyone is talking about.
As a young, talented Scottish player, Celtic are bound to be linked with him. However, given their strategy of buying relatively cheap with the intention of selling for a sizeable profit further down the line, an outlay of a reported £6 million to meet Dundee United's asking price would represent a massive change of attitude for the club hierarchy.
As well as signing two new deals in quick succession, Gauld has also stated a preference for moving abroad when he does finally decide to move on, making it increasingly unlikely he will ever don the Hoops.
Previous permanent club(s): None
This season: 12 goals, eight assists (23 games)
Market value: £225,000
Too soon? Probably, but there is something about Stevie May's all-round play this season that makes it seem like an avenue which should be explored. If not in January, then come the season's end.
The Perth native has come through the ranks the right way. Two loan spells with lower league teams proved fruitful, bearing 45 goals in 57 matches.
So far he's made the step up to the senior team with great aplomb, instantly becoming the Saints star player.
Similar to Billy McKay, any talk of a move to Celtic would depend on whether Neil Lennon viewed May as an upgrade to what he already has at his disposal.
But with goals and assists in almost equal measure, and a penchant for a spectacular finish and ever-improving link-up play, there seems to be no reason why May wouldn't be a useful addition to the Parkhead playing staff in the future.