KRIS BOYD has slammed Dundee United midfielder Calum Butcher for his challenge on Celtic ace David Turnbull.

Butcher was introduced into the action shortly after half-time today and he was carded moments after coming on. 

Referee Bobby Madden flashed a yellow after the Terrors midfielder showed his studs and connected with Turnbull just below the knee.

Boyd reckons the challenge was worthy of a red card and he admits Turnbull was lucky to not pick up a serious injury.

On Sky Sports, he said: “It’s a red card all day long. There’s no doubt about it. He’s high, it’s at speed and he’s in endangering the safety of his opponent.

"David Turnbull was lucky to get away with it. It’s a red card all day. I know I said it the other night but the sooner we get VAR in Scottish football the better because that’s a red card.

“David Turnbull is very lucky that he didn’t get a really, really sore one."