Leigh Griffiths: Celtic & Scotland striker to return to training after absence
Leigh Griffiths will return to training with Celtic this week after being out of football since early December dealing with mental health issues.
The Scotland forward, 28, will begin "fitness and performance work" with medical staff with a view to returning to full training "in the future".
Celtic manager Neil Lennon said there is "no timescale" on a return to first-team action for the striker.
"I'd like to thank everyone for showing me such support," Griffiths said.
"I am so grateful to the club for everything they have given me and the way in which they have supported me so strongly."
In December, then Celtic manager Brendan Rodgers said Griffiths would be "out of football for a little period of time" because "he's reached a point where it's a struggle for him".
There was speculation he had problems with gambling, but the striker said that was "laughable", insisting he was absent for mental health reasons.
Lennon, who said 10 days ago he hoped to have the player back before the end of the season, said he was "really pleased" by his return.
"We will make sure we work with him on the best, most productive way forward," he added. "We will not rush him in any way and we will allow him to take things slowly and at the pace he is comfortable with.
"We'll continue to give Leigh every support to make sure that his health and wellbeing are our number one priority."
Griffiths had made 22 Celtic appearances - scoring six goals - in a campaign that had been disrupted by injuries. His last outing was against Kilmarnock on 8 December.