Celtic's new signing Kolo Toure has not travelled to Dublin for Saturday's International Champions Cup clash with Barcelona, live on Sky Sports 1 HD from 5.45pm.
The 35-year-old Ivory Coast international joined the Scottish champions on a free transfer after leaving Liverpool when his contract expired earlier in the summer.
But with Brendan Rodgers' side set to take on the La Liga giants at the weekend, Toure will not be risked ahead of Wednesday's crucial Champions League second leg with Astana.
First-team coach John Kennedy, travelling with the rest of the squad to Ireland on Friday, told Sky Sports News HQ: "Kolo is still working fitness-wise, he will stay back and do some extra work.
"It's probably a bit early for him to play on Saturday so we think if he stays at home we can get a few extra sessions in fitness-wise and we can look at that and assess that again on Monday."
Asked if Toure would play in the Champions League qualifier, Kennedy added: "It depends how he will come through the next few days of training.
"If he shows fitness levels that we find to be good enough then he is an option but we have to just go with what we have got."
Other fitness concerns for Celtic are with defenders Erik Sviatchenko and Mikael Lustig, Kennedy confirmed the pair would remain in Scotland to help their recovery.
Although the game against Barcelona is of less importance, Kennedy insisted the fixture would be helpful for the squad to experience playing a team full of world class players.
"I think it's a game where we can see where we are at in terms of performance levels playing against a top side," he said.
"This is where you test yourself and see exactly where you are at, and it gives you a marker. You know we have done a lot of good work pre-season against different opposition but we are coming up against a different level now.
"You see individually where different players are at but, more importantly, collectively as a team how we can handle playing against that calibre of team.
"It's a great test, it will be a good match for us and it will be a good atmosphere over there as well."