Cameron Carter-Vickers will not make his comeback against Atalanta despite training ahead of the Champions League clash.
The centre-back trained at Celtic Park on Tuesday morning, but did not make the journey to Bergamo in Italy.
Manager Brendan Rodgers said: “He hasn’t travelled. Greg Taylor hasn’t travelled as well. Greg should join the group on Friday. Cam, we will see when we get back.”
The United States international’s previous appearance was in the 5-1 opening Champions League win over Slovan Bratislava. He did not finish the game after a lingering toe injury took its toll.
Celtic have only kept one clean sheet in five matches during his absence and lost 7-1 against Borussia Dortmund in their second Champions League league phase game.
Left-back Taylor has been sidelined since the Dortmund defeat with a calf problem.