Calvin Miller and Anthony Ralson have become first-team players at Celtic but Jamie McCart is still waiting for his chance.
Celtic manager Brendan Rodgers has given Anthony Ralston and Calvin Miller a chance this season - is Jamie McCart next in line?
19-year-old defensive duo Kristoffer Ajer and Jamie McCart will return to Celtic with their reputations enhanced - but who impressed Brendan Rodgers most?
Jamie McCart has thrived with regular first-team action at Inverness Caledonian Thistle - and a place in Celtic's first-team appears to beckon.
O'Connell, on loan at Walsall, is out of contract at the end of the season and may be usurped at Celtic by another talented youngster.
The young Celtic defender has impressed on loan at fellow Premiership side Inverness.
The young defender is going from strength to strength at Inverness after joining from Celtic last month.
Celtic youngster Jamie McCart is currently on loan at Inverness Caledonian Thistle.
Rodgers wants to give youth a chance - luckily he has a few talented teens ready to step up.
We profile five of Celtic's biggest hopes for the future - Jack Aitchison, Aiden Nesbitt, Jamie McCart, Calvin Miller and Anthony Ralston.