CELTIC face a defensive dilemma ahead of Thursday's Europa League opener against Red Bull Salzburg.

Manager Ronny Deila has confirmed that he expects both Mikael Lustig and Adam Matthews to miss the Group D tie in Austria as neither right-back will have recovered in time from the groin injuries they picked up last month.

Both players had to withdraw from their respective international matches last week. With Darnell Fisher also still sidelined after an operation at the end of last season, that means Efe Ambrose will be asked to continue in the full-back position.

The list of absentees will also include Charlie Mulgrew and James Forrest. Mulgrew is undergoing treatment on the knee injury aggravated while playing for Scotland in Germany and which kept him out of the 2-1 win over Aberdeen.

Forrest has managed only three appearances this season, one from the start. He has not played since coming on as a sub against Dundee United on August 16, pulling up with a recurrence of his hamstring problems at the end of the match.

Deila reckons he will be out for at least another four weeks. The manager confirmed: "He has started running, but it takes time. I don't know a date when he will return."

The news on Lustig and Matthews is slightly better, and Deila reported: "There is progress, but, again, it takes time. I hope they can start training now a little bit.

"But, we will have to see. It is hard for me to say when they will be fit to return. I think Thursday's game is too early for them."

At least skipper Scott Brown appears to have emerged from his comeback match against Aberdeen without any reaction.

The midfielder was taken off after 62 minutes, but this was pre-planned and he will lead the team out against Salzburg.

Before the squad fly to Austria on Wednesday, Aleksander Tonev should know if he is to face a charge of racially abusing Shaleum Logan in Saturday's game.

The Bulgarian is accused of twice making racist comments towards Logan in the second half. A Celtic spokesman confirmed Tonev denies the allegations, saying: "We have spoken to the player and he has stated that the accusation made is not true."

Logan brought the matter to the attention of referee Bobby Madden during the game. He also informed captain Mark Reyonolds, who raised the allegation with Madden.

Aberdeen officials then informed the referee of the allegations after the final whistle, and SPFL delegate John Connelly was also made aware of the alleged abuse.

The SFA will await Madden's report, then the Compliance Officer will invite both clubs to make their comments and present any evidence they have.

Based on all of this, the Compliance Officer will decide if a Notice of Complaint should be issued against Tonev. However, without any independent witness, it would appear to be one player's word against another's. As such, it is considered unlikely the matter will be taken any further.