David Moyes has been installed as the bookmakers' favourite to replace Ronny Deila as Celtic manager.
The Scotsman was sacked by Real Sociedad on Monday after just one year in charge of the Spanish club.
Moyes, who spent 11 years at Everton, switched to La Liga in November 2014 after he lasted just 10 months as Manchester United manager.
Deila remains as Celtic boss, but the Norwegian is under pressure due to the club's poor form in Europe, which earlier in the season saw them fail to qualify for the Champions League and they are now in danger of dropping out of the Europa League in the group stage.
According to the Daily Record, Moyes, who played for Celtic for three seasons, is the favourite to take the job should bosses at Parkhead opt to dismiss Deila.
Moyes's assistant Billy McKinlay was also sacked by Sociedad.