Neil Lennon has questioned why Celtic had to play against Hearts on Sunday rather than Saturday, feeling it has left them at a disadvantage ahead of their Champions League clash versus Atletico Madrid.
He pointed to examples in other leagues where European participants had their domestic fixtures scheduled in a way that allowed them to have more recovery time.
Lennon reckons Scottish clubs are being let down the schedule. Speaking to PLZ, he said: "Celtic are playing on a Sunday afternoon when they have got a Champions League game on the Wednesday night.
"Atletico Madrid played on the Saturday evening, why are Celtic playing on a Sunday afternoon?
"Now they have only got Monday and Tuesday to recover, and then they are playing against Atletico Madrid. I know it might be for TV, but Man United played on Saturday evening.
"Arsenal played on Saturday evening at 5.30pm. Man City played; all their teams that are in the Champions League played on the Saturday.
"The Scottish representatives play on the Sunday with a day less recovery. I just don't get it."
Meanwhile, Jeong Ho-yeon has opened up on reports linking him with a move to Celtic.
The 23-year-old is a player that the Scottish champions are said to be keeping tabs on ahead of the January transfer window.
In recent years the Hoops have become renowned for tapping into the Asian market with several players arriving from the J-League and K-League.
In terms of Korea, Oh Hyeon-gyu, Yang Hun-jun and Kwon Hyeok-Kyu have all arrived within the last year.
Jeong has had recent success in the K-League 1 after helping his side gain promotion last season.
When asked by Korean outlet Sports G about reports linking him with Celtic, he said: "I know that such stories are coming out around me.
"In fact, there has never been a specific or direct contact so far. I heard the same story from my team and agent. I just want to be faithful to my team in every moment."
