Celtic are busy battling in their UEFA Champions League play-off round and while no signings can be made for the second leg next week in Kazakhstan, plans still need to be put in place for two scenarios; making the group stages of the competition and dropping into the UEFA Europa League.

The kind of players the Hoops can bring to Celtic this summer perhaps rest heavily on whether they qualifying for the group stages and many fans have been suggesting that's why they've been rather quiet in the transfer window so far.

The only arrivals so far have been Olivier Ntcham, Jonny Hayes and Kundai Benyu, three transfers of varying value and potential impact on Brendan Rodgers' first team.

With just a few weeks left before the end of the window, some fans are growing anxious they won't end up doing the business in key areas you might suggest the Hoops need.

However, there are FOUR big potential transfers still out there, players who have recently been linked with Celtic, who could still sign...

Rivaldo Coatzee

Rivaldo Coetzee was linked with a move to the Scottish champions this weekend past when The Evening Times reported that he was one of the names Celtic were looking at signing before Tuesday's signing deadline for the Astana tie.

Still just 20 years of age, Coetzee is winning plaudits in his homeland for assured defensive displays beyond his age. He's already made close to 100 appearances for Ajax Cape Town and has already won 22 caps for South Africa.

In 2014 he became the youngest ever South African internationalist and while that record has subsequently been broken it's a sign of his massive potential.

Making the move to European football can often be difficult for African players but Coetzee is better placed than most with the experience already behind him and the fact he would be working with one of the best youth coaches around in Brendan Rodgers.

Is he the man to shore up a stretched Celtic back line?

Abdul Majeed Waris

Football Soccer - Paris St Germain v FC Lorient - French Ligue 1 - Parc des Princes Stadium, Paris, France - 21/12/2016 - Paris St Germain's Blaise Matuidi in action with Lorient's Majeed Waris. REUTERS/Benoit Tessier

Linked with Celtic in The Daily Mail at the start of August, Abdul Wajeed Maris is said to be tracked by multiple British clubs including West Ham, Fulham, Brighton and the Hoops themselves.

Making a name himself at Ligue 1 side Lorient, the Ghanaian international reached double figures in French football last season which would suggest he has more than enough about to be a success in the Scottish Premiership.

He made his name in Europe in Sweden, winning the Allsvenkan Player Of The Year award in 2012 after scoring a fantastic 26 goals in 35 appearances for BK Hacken.

While his he clearly has prowess as a centre-forward, perhaps crucially for Celtic he can also play on the left or right wing, potentially solving Celtic's issue of having quality back-up for Moussa Dembele and Leigh Griffiths without having the player waste time on the bench. If he can also provide competition in other areas, he should see plenty of game time.

Patrick Roberts

Britain Soccer Football - Celtic v Manchester City - UEFA Champions League Group Stage - Group C - Celtic Park, Glasgow, Scotland  - 28/9/16
Celtic's Patrick Roberts comes on as a substitute
Reuters / Russell Cheyne
Livepic
EDITORIAL USE ONLY.

The Patrick Roberts saga is of course one that has rumbled on all summer and as recently as Tuesday, media outlets such as The Scottish Sun were reporting that the Hoops were locked in talks with Manchester City about a potential return to Glasgow for the 20-year old winger.

Whether on loan or on a permanent basis, Celtic fans would absolutely love to see him return to the club and find the kind of form that allowed him to score 17 goals and assist 21 more in just 18 months at the club.

He has the kind of ability to make a real impression both domestically and in the UEFA Champions League and was arguably Celtic's best player in the final two months of last season, often providing the spark need to get over the line in matches on their way to an unbelievable unbeaten treble.

Can Celtic convince Man City to part with a player they are not utilising at the Etihad?

Steven Caulker

As noted, the centre of the defence is a big priority for many Celtic fans. The perception is that aside from Jozo Simunovic, the Hoops lack the real quality that can provide consistency in European football. They need more options and at the very least more cover with both Dedryck Boyata and Erik Sviatchenko missing for the next couple of months.

In many ways Steven Caulker fits the bill; he has top-flight experience in an elite league, he's worked with Brendan Rodgers previously and he's in need of a club that he can make his home and rebuild his career.

Celtic could be that place with The Daily Mirror reporting last month that the Hoops were in talks to bring him to Glasgow. While those stories have gone quiet in recent weeks, he's still not getting league games at Queens Park Rangers, playing in neither of their Championship fixtures so far. His only start this season came in a League Cup win against Northampton Town.

With the Hoops in need of a defender and Caulker in need of a new club, is it to be a match made in heaven?