Celtic goalkeeper Vasilis Barkas faces a sweat to be fit for the crucial showdown with FC Midtjylland, while Mikey Johnston limped off with what looked like a hamstring injury against Bristol City.
The Parkhead club face their first Champions League qualifier on Tuesday as they look to return to the group stage for the first time since the days of Brendan Rodgers.
Star striker Odsonne Edouard went off injured against Charlton, leaving manager Ange Postecoglou with a sweat for his first competitive match.
And the problems appear to be mounting as Celtic picked up two more knocks in their third pre-season friendly.
Goalkeeper Vasilis Barkas had a shaky first season but has been named in the starting XI for each of the games so far.
However, on Tuesday he suffered an injury in the warm-up and was later seen sitting on the sidelines with his fingers strapped up.
And midway through the first half Johnston pulled up with what looked like a hamstring injury and was also forced to limp off.
And Postecoglou was forced into a third change of the match when Karamoko Dembele was also injured late in the half.
A number of departures have left the manager's squad looking thin ahead of the Midtjylland game, while defender Kris Ajer hasn't played a minute in pre-season as he seeks a move.
Ryan Christie, whose contract is up in January, was also left out of the squad entirely for the Bristol City game.
