Former Rangers manager Graeme Souness described Allan McGregor's sending-off against Hibernian as "stupid" and insists the goalkeeper is old enough to know better.
On the day striker Alfredo Morelos came off the bench after a four-game ban, the 37-year-old goalkeeper kicked out at Marc McNulty in the 89th minute of the Light Blues' 1-0 win over Hibs at Ibrox.
The Govan men had to see out a dramatic finale with Ross McCrorie in goal, having used all three substitutes.
Boss Steven Gerrard later admitted he was running out of ideas to tackle Rangers' discipline problems, which have brought 12 red cards this season.
Former Gers player/manager Souness, speaking at The Kris Boyd Charity annual golf day for Mental Health at Turnberry, said: "There are sendings-off and sendings-off. There are sendings-off when the games are a bit meaty and aggressive and you go for challenges and you are maybe a bit late.
"And there is the stupid one yesterday, for that.
"Someone at 37 years old shouldn't be getting sent off for that, lashing out unnecessarily.
"The manager can talk until he is blue in the face but that has to come from the player, at 37 you would think he would know by now.
"You keep pointing it out to them that ultimately you are letting your team-mates down. Like (Alfredo Morelos) did in the last Old Firm game.
"You are deserting the trenches, leaving your pals to it when you are getting sent off for something stupid.
"I think it is different if someone is overly aggressive to you and you go back in a manner that gets you a card."
Kilmarnock striker Boyd insists McGregor, his former Rangers and Scotoland team-mate at Ibrox, will have woken up "embarrassed" by his actions and believes Gerrard has to quickly address Rangers disciplinary problems.
He said: "I think Steven needs to do something, he needs to make a statement.
"You go back to Rangers managers like Graeme Souness, Walter Smith, would they stand for it? No. They would have dealt with it right away.
"The best thing for Steven to do now is address it and address it properly, make an example of someone.
"I know people saying leaving Alfredo Morelos out the team was making an example, it wasn't, because Jermain Defoe had come in and done well.
"Had he not, Alfredo Morelos would have started when he came back.
"There needs to be a stance made, that you can't behave the way some players are behaving on the pitch."
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