Ronny Deila says Celtic must "take more care of" James Forrest as the winger pursues a sustained injury-free period.
The 23-year-old, who missed September and October, did not feature in Saturday's draw with Ross County but could face Partick Thistle on Thursday.
"He has been out for 550 days in the last four years, which is almost two years," explained manager Deila.
"You need to take it slowly and build it up again. We want quick steps but we have to be careful."
Scotland cap Forrest drew praise from national team coach Gordon Strachan after scoring in Celtic's defeat of St Mirren in mid-December, three weeks after the forward had returned to first team action.
However, a knock picked up in the 2-1 defeat by Dundee United sidelined Forrest against County.
"He is a special boy that we need to take more care of, more than a lot of the others because he has been out for a long time," added Deila.
"Now he has been injury-free for two months. He got this little one but it is nothing serious. So this is going very well.
"If you push him too hard then he is going to be out again.
"He has progressed. Against Dundee United he was more active than he was before but you need consistency over time to get the best out of James.
"The problem has been pulled muscles so we need to get his fitness up.
"It is one thing is to run, another to play football. You get football fitness by getting on the pitch.
"But he is in a good place now. He played 90 minutes against Dundee United and I think you have to go back a long time for his last 90 minutes."