Ronny Deila continues to keep faith in injury-jinxed James Forrest as the Hoops winger prepares to make his latest comeback.

The 23-year-old former Parkhead youth player has suffered from various ailments since making his debut as substitute - and scoring - in a 4-0 win over Motherwell on May 1, 2010.

Forrest's undoubted talents have won him international recognition with Scotland but, since taking over from Neil Lennon in the summer, Deila has still to see the best of the player who has made 10 appearances in 10 months.

A knock picked up in the recent 2-1 Scottish Premiership defeat by Dundee United at Tannadice meant he missed the goalless draw against Ross County on Saturday.

However, Forrest will return to the squad for the trip to Partick Thistle on New Year's Day, and the Celtic boss explained why he is nursing the player back to full fitness.

Deila said: "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.

"He has been out for 550 days in the last four years, which is almost two years, so you need to take it slowly and build it up again.

"Now he has been injury-free for two months. He got this little one (injury) 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.

"We want quick steps but we have to be careful."

The loss of five points in Celtic's last two games meant Aberdeen were able to move to within two points of the champions with their 1-0 win at Inverness on Sunday.

The Dons could go top of the table against St Johnstone on January 1, at least until the Hoops take on Partick at Firhill later in the day.

Deila denied that his side go into 2015 in poor form but admits "stupid" points lost early in the season have hampered title aspirations.

The Norwegian said: "I don't think we have been poor. In the last 10 (league) games we have had eight victories and one defeat and one draw.

"And we have should have taken something out of the game in which we got beat.

"In the last two games we haven't taken the points we wanted but we are controlling games.

"Aberdeen are on a good run and they are a good team but we have to concentrate on ourselves and continue winning games and then the other team has to be very good to cope with us.

"I had hoped for more points. We lost some stupid points at the beginning of the season, but in the last weeks we have been quite consistent and we are controlling games more than we did before."