St Johnstone defender Frazer Wright will sit out tomorrow's match against Celtic after getting concussed and breaking his nose during their draw with Kilmarnock.

Manager Tommy Wright yesterday revealed the damage had been inflicted by one of his team-mates. The former Killie centre-back was floored in the closing stages of the 0-0 Perth encounter after being felled by Steven Anderson's flailing boot and he had to be replaced by Tam Scobbie for the closing 15 minutes.

"Frazer is fine now that we've managed to remove Ando's boot from his head," Wright joked. "He's got a broken nose and was concussed. If that's what your mate will do to you, then God help us!

"I don't think Ando meant it - I'd hope not anyway because they're pals. It was just typical of the pair of them and how desperate they are to defend everything that comes into the box.

"Looking back at it, Frazer could probably have headed it back to Alan Mannus but Ando had other ideas. We're having a laugh and joke about it, and the lads will be giving Ando some stick as usual, but head injuries are serious.

"In all likelihood I would have left Frazer out against Celtic anyway because playing Saturday and then Wednesday is tough. But with concussion you can't take any chances.

"Tam Scobbie will come back in and he'll be desperate to play again. He's been unlucky to be left out but I had my reasons against Dundee United and just stuck with Frazer for the Kilmarnock game. We have competition for places and that's healthy."

Boss Wright watched Celtic hammer four past Aberdeen to all but seal the championship.

"I thought Aberdeen were excellent in the first half," said Wright. "But the thing is, if Celtic are going to score you have to make them work for it.

"We were very disappointed with the two goals we lost against them recently and Aberdeen will be annoyed at the first one they lost. When you play in these games against Celtic you can't afford to give them the first goal easily because with the quality they have they can open you up.

"If you go gung-ho against them they can slice you apart so it's about getting the right balance between being defensive but also offering something in attack.

"We'll go there, try to stick to our game plan and give them problems at the other end at the same time.

"When you go there it's about being strong, making the right decisions and concentrating. They will have a lot of the ball because they're at home so you have to be in the right frame of mind when you have possession."