Manager Brendan Rodgers said the centre-half's absence made him "sad" and that he had to put his faith in "players who want to be here".

Boyata responded by posting a video of him receiving treatment.

"Unfortunately, I could not play because I'm not yet 100% operational," the 27-year-old said on Instagram.

Fulham had a multi-million pound bid for Boyata rejected last week before England's transfer window closed.

His agent, Jacques Lichtenstein, was subsequently quoted as saying that, because the Belgium defender is in the final year of his Celtic contract, he could not afford to risk playing when not 100% fit.

Responding to suggestions he had not travelled to Greece because of a 'convenient' injury, Boyata posted a video showing treatment to his back and thigh that he described as a "muscular work session to come back even stronger on the pitch".

Celtic go into the second leg against AEK with their progress to the play-off round of Champions League qualifying hanging in the balance after drawing 1-1 at home last week.

Boyata, who helped Belgium reach this summer's World Cup semi-finals, added that he was "with all my team-mates to bring the qualification".

Belgian website DH.be quoted the defender as saying: "When I hear I've refused to play since I came back from vacation, it's wrong.

"Last Thursday, I hurt myself when I slipped in training and I held my leg immediately.

"The physio saw it and examined me right after the session. I put ice for 30 minutes on my leg and, the next day, I specified I had pains.

"The exams proved I could not play against Hearts and, since then, I'm doing everything I can to be ready as quickly as possible."

Boyata stressed he had full confidence in his agent and that, since joining Celtic from Manchester City in 2015, he had played a number of times while not 100% fit.

Before the match against AEK, manager Rodgers refused to be drawn on whether Boyata had played his last game for Celtic.

Analysis - Former Celtic midfielder John Collins on BBC Radio 5 live

Dedryck Boyata posted a video of him receiving treatment on Instagram

"Celtic's business model in recent years has been to sign younger players cheap, develop them and sell them on when they go into the last year of contact.

"They have done it with so many players - Virgil van Dijk, Victor Wanyama and Stuart Armstrong in the summer - so I would imagine they would sell Dedryck.

"They signed two central defenders in January in Jack Hendry and Marvin Compper, but they haven't really produced and Dedryck has been the number one alongside young Kristoffer Ajer.

"I think they will sell him, but they have refused Fulham, so the English market is closed and the only market now is the Continent."