Leigh Griffiths will return to Celtic this week after taking time off to deal with personal issues.

The Scotland striker has been on leave since December to receive professional help.

Celtic confirmed that the 28-year-old would now resume fitness work at the club's Lennoxtown base.

He will work with medical and sports science staff, with a view to returning to first-team training in the future.

Griffiths said: "I'd like to thank everyone for showing me such support across the past few months.

"I am so grateful to the club for everything they have given me and the way in which they have supported me so strongly.

"The Celtic supporters, too, have been a huge source of inspiration and strength for me and I want to thank them all sincerely for staying with me. I know it will be a long road back but I am ready to do all I can to get there."

Celtic manager Neil Lennon said there was no schedule for Griffiths' return to the first team.

He said: "We are really pleased that Leigh will be looking to get things going again at Lennoxtown and be making a phased return to training.

"In no way will we put any timescale on a possible return to the first-team. Instead, we will make sure we work with him on the best, most productive way forward.

"He will really be focusing on his own programme at the moment and then we will see what progress we make from there. We will not rush him in any way and we will allow him, of course, to take things slowly and at the pace he is comfortable with.

"As the club has been doing throughout the last period, we'll continue to give Leigh every support to make sure that his health and well-being are our number one priority.

"We'll work with him to ensure he has everything he needs to give him the chance to get back to where he was, but understanding totally that he will need time and space.

"It will be great to see him back, even at this very early stage, and we'll make sure we give him our total support."