Brendan Rodgers has joked that FIFA's proposed new blue card rule for sin bins would not work in Scotland because of the colour.
The idea for an additional punishment for offences sending players to a sin bin at the side of the pitch has been discussed this week.
It could be signed off by IFAB as soon as next month when the football rule-makers meet in Scotland.
If approved, then domestic leagues can sign up for a trial scheme but Rodgers is not impressed with the potential new rules.
As well as joking about how the colour of the cards could cause problems, the 50-year-old also made clear it would simply "complicate" the game.
"As soon as I seen it I thought 'I work in Scotland, they better have a green card as well as a blue card or we might be in trouble
"Just don't complicate it - make a decision. Whether it's red, yellow or no decision - we don't need a blue card up here, that's for sure."
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Rodgers also confirmed that Alistair Johnston is out of Celtic's Scottish Cup tie against St Mirren this weekend.
The defender suffered a sickening head injury in the early stages of the Hoops' 2-1 win over Hibernian on Wednesday night.
The Canada international won his side a penalty after Hibs' Nectarios Triantis collided with him in the air.
It came at a cost though, as the right-back, 25, was substituted off, with Anthony Ralston deputising in his absence.
Johnston was rushed to hospital for checks - but he gave the thumbs up to fans on social media after Adam Idah secured the victory at Easter Road with his second spot kick of the game.
However, now, Rodgers has revealed to the media that the defender suffered a suspected fracture and will therefore miss Sunday's fifth round tie in Paisley.
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