Brendan Rodgers was unable to explain Dedryck Boyata's absence from the Celtic team that crashed out of the Champions League on Tuesday.
Celtic lost 3-2 on aggregate to AEK Athens to miss out on a place in the play-off round of UEFA's lucrative continental club competition.
The centre-back's agent revealed this week that Celtic received offers for Boyata, including from Fulham and Fenerbahce, but he hit out at the Scottish side for rejecting them and not offering a new contract.
Rodgers insists Boyata is physically able to feature for the team, but the defender, who made three appearances for Belgium at the World Cup, did not make himself available for the game as speculation over a potential move away from Celtic Park increases.