Kristoffer Ajer, Ryan Christie and Liam Scales.

What do they all have in common? They were loaned to a fellow Scottish Premiership club and came back and became a rip-roaring success at Celtic. If 25 is reputedly the magic number for Celtic boss Brendan Rodgers. That's the ideal number of first-team players he'd like in his squad, so more bodies are needed to be shipped out the Parkhead exit door. That stands to reason - right?

Now, if we also accept as a general rule of thumb that Celtic's resident bench warmers and fringe players who make up the squad number would command a regular first-team spot elsewhere - i.e. in every other Scottish Premiership club - then why not do those teams a turn and loan those players to them.

In the last few days, Kwon Hyeok-kyu has checked in at Paisley as he looks to kickstart his career in Scotland with Steve Robinson's St Mirren. Adam Montgomery has been recalled from a loan spell with Fleetwood Town to join Motherwell and he will spend the remainder of the campaign at Fir Park.

READ MORE: Celtic project Kwon Hyeok-kyu joins St Mirren on loan

They should not be the only loan deals that Celtic conclude in this window with fellow league clubs. Celtic have a plethora of players that need to go out on loan so that is why it makes perfect sense to offload Kwon to St Mirren and Montgomery to Motherwell to see if it can be the making of them. It was certainly the making of Ajer, Christie and Scales who all flourished on their respective returns to Paradise after loan spells with Kilmarnock (Ajer) and Aberdeen (Christie and Scales).

Rodgers has 32 senior players at his disposal and with the best will in the world, some players will not kick a regular ball for Celtic ever again. That's football. That's life.

As Rodgers said back in October: “It is more quality than quantity, for me. I think there will be more out than coming in. I think there will be players who will be here for six months and won’t have played.

“Like I’ve said before, it is no fault of them. The squad is obviously a lot bigger than I would want. So, I think there will be more players who will look to go out and get game time. Hopefully over the coming windows, we can look to improve the quality of the squad. Listen, we have enough - what I would say - development players. I think it is clear. And I love that, it is what I have done all my life is work with those players. But you certainly need ones that can come in [and make an immediate impact].

"We already have a number of those development players, so it is genuine quality we hope we can bring in across the coming windows. Your squads are 25, which is 22 plus three goalkeepers. It is not ideal. I think some younger players were going to come in and see how they develop. Just after the summer window shut it was a case of speaking then to some of the players that didn’t get out. I said, listen let’s see how we go over the course of the next six months. If it doesn’t quite work out with game time then, of course, we’ll look at it in January.

“Some of those players have had game time, and will be happy, and there will be others that feel they will want to play.”

Celtic Way:

READ MORE: Liam Scales' amazing journey to Celtic: Mentors on his meteoric rise

Swedish defender Gustaf Lagerbielke who has been linked with a loan move to Serie A in Italy should jump at that chance. Failing that then a loan to a club closer to home in Scotland's top flight should be arranged as an immediate priority. Lagerbielke may not be fancied by Rodgers at this time but name a Scottish top-flight club that would not benefit from the centre-half bolstering their ranks.

Midfielder Odin Thaogo Holm should also think seriously about taking a leaf out of compatriot Ajer's book and crave the same after seeing his game time limited in G40. Australian Marco Tilio is another who could benefit from a loan spell to prove his worth away from Celtic Park and you get that feeling that with fellow Aussie Nick Montgomery in situ at Easter Road then the player could do worse than hone his talents for a brief spell in the capital and come back to Glasgow refreshed and ready to kick his career on again.

Mikey Johnston could also do with going out on loan or even a permanent transfer away from the men in green and white. Although he hit a purple patch around December and netted twice in a 3-0 win over Dundee at Dens Park on Boxing Day many still feel that the player does not have any kind of future with Celtic Whilst we are it Celtic is also in the market for a striker and let's spitball here could the club could do worse than offer Johnston as a makeweight in a deal with Hearts or Aberdeen for Lawrence Shankland or Bojan Miovski?

This is why Celtic loaning players out to other Scottish Premiership clubs is a policy that the club should be looking to do more of.

It's a win-win situation for everybody concerned. It does appear to be the ultimate no-brainer. The player gets valuable and regular game time. The player gets familiar with the rough and tumble of Scottish football as well as getting to know the Scottish terrain inside out.

Not only that but this particular season of all is threatening to be the closest one yet in terms of an actual two-horse title race in years. Why shouldn't Celtic give their opponents a hand, especially if those players can help inflict some damage on their city rivals in the process? Scales scored a vital goal for Aberdeen in a 2-0 win for the Reds at Pittodrie last season which all but ended any late title challenge from the Light Blues.

It is hardly a new or novel concept or idea but it is one that Celtic have scandalously underplayed as well as undervalued in recent years with the exceptions being Ajer, Christie and Scales, of course, and that paid huge dividends. There is not a Celtic supporter out there who will not be interested in the fortunes of Kwon despite his defection to Paisley. They will be curious to see if the 22-year-old can make a valid contribution to the St Mirren cause in terms of goals and assists and if he can shine on that platform.

The same goes for all the other Celtic loanees, the faithful will be desperate to see those players farmed out make a fist of it and be successful in the hope that they can come back to Parkhead and contribute meaningfully to the cause. The loan deal system is there to be utilised and worked to clubs like Celtic's advantage and benefit at all times.

It's a bit like comedian Peter Kay's father when he discovered garlic bread for the first time and declared that he had tasted the future. Celtic loaning out players to fellow Scottish clubs is the present and the future...or at least it should be.

If there is any doubt about that then just ask the likes of Ajer, Christie and Scales.