Angry Celtic have revealed the club is "addressing" comments made by former Kris Boyd on Callum McGregor.
The former striker wrote about the midfielder after he battled through a fractured cheekbone to feature against Rangers.
The Celtic captain would play a key part in the 3-0 demolition of the defeat of Gio van Bronckhorst's side as they slipped from top spot in the Premiership.
In his column for The Scottish Sun, Boyd controversially insisted Rangers players should have been "testing out" the mask.
That enraged huge sections of the Celtic support and the club have now confirmed they are looking into comments made by the pundit.
A statement read: "With regards to comments made by former professional footballer Kris Boyd concerning Callum McGregor's injury, we can confirm that the matter is currently being addressed by the club."
Boyd said: "Look at Celtic. Callum McGregor played with a fractured cheekbone.
"The fact he managed to get through the 90 minutes without anyone testing out that face mask is another story, but his commitment to the team was tremendous."