Celtic are hopeful that Kris Commons, James Forrest and Scott Brown will be fit for Champions League duty despite being injury doubts for Paisley.
Neil Lennon's side visit Barcelona on Tuesday after travelling to face St Mirren in the Scottish Premier League.
And the manager said: "This weekend may be too soon for them, but they might have a chance for Tuesday."
Winger Commons pulled a hamstring playing for Scotland, with the other two having dropped out of the squad.
Captain Brown aggravated a hip complaint during the 2-1 loss to Wales on Friday, while fellow midfielder Forrest missed that game and a Tuesday defeat by Belgium during which Commons picked up his injury.
"James did his groin in training with the Scotland squad and Scott, as you know, has this ongoing problem," said Lennon.
"I felt he was playing very well against Wales but obviously he couldn't continue after half-time, so we are assessing him as we go along."
Greece striker Georgios Samaras, Honduras full-back Emilio Izaguirre, Venezuela forward Miku and Kenya midfielder Victor Wanyama have still to rejoin Celtic training after their international travels.
"We are hoping to see them later on today or tomorrow, but we have no reports of any knocks or niggles," added Lennon.