Boyata had claimed to be injured for Celtic's Champions League qualification clash against AEK Athens, however Brendan Rodgers dismissed this in his post match press conference.
The Belgium international's absence did his club no favours, with the 'Bhoys' falling to a 3-2 aggregate defeat in the Greek capital.
The 27-year-old has now returned to training but only after he apologised to his teammates, Rodgers confirmed.
The former Liverpool boss believes that he can revive his Celtic career, after the club rejected a bid from Seville for his services.