Celtic manager Ronny Deila confirmed Anthony Stokes has been dealt with by the club over a disciplinary matter.
BBC Scotland understands the striker returned to the club late following a trip to Ireland.
He was left out of the squad for Thursday's 3-3 Europa League draw with Inter Milan but could be involved for Sunday's league match against Hamilton.
"There was a small thing we had to deal with and it was done internally," Deila said.
Stokes watched Thursday night's dramatic draw with Inter from the stand at Celtic Park.