TRUE to form, Mick McCarthy produced a light-hearted comment on the serious subject of strict refereeing that has seen matches ruined by a welter of yellow and red cards.

"They'll have to cancel the League at Christmas because there will be no players available," he said with a smile.

But the Sunderland manager is adamant his side will not take a backward step, even though suspensions accrued from cautions and sendings off could undermine their promotion push.

Sean Thornton, who hardly fits the archetypal image of a midfield hardman in the style of Kevin Ball, was dismissed at Stoke City on Tuesday for two bookable offences.

McCarthy insists, however, the hardline stance taken by referees will not affect his team's approach in tomorrow's game at Derby County. He said: "If my lads stopped challenging, they'd have more than a problem with the referees; they'd have a problem with me.

"We'll keep competing for the ball, but I don't think we're a dirty team in any way.

"I've told the players that if they go into a 50-50 challenge and win the ball but clean everything out, and they get booked, that's all right.

"I don't want bookings for dissent, or to see my players kicking people off the ball, but I insist we compete and tackle.

"I saw some stats on television regarding the number of yellow and red cards in the Premiership, and they were amazing.

"There has been a clampdown over the years, not just this season, and players are getting booked if they win the ball from the side and also take the player.

"Previously, as long as you won the ball the challenge was acceptable. But it appears to me that there are now more bookings for things that are innocuous.

"And if you get booked for one challenge, you're walking a tightrope and you can get sent off quite easily.

"Referees put themselves in a position sometimes by booking a player for the first foul, and it's then impossible not to give a second yellow card when the next challenge comes in.

"But I've got to say I wouldn't want to referee the games for a gold pig, never mind a gold clock."

Sunderland captain Jason McAteer, who has just returned from injury, is facing up to six weeks on the sidelines with a hamstring strain.

McCarthy said: "It's not the same hamstring that Jason hurt before. He did all his rehab and was doing well, so he's been unfortunate."

Gary Breen will be out for three weeks with a groin injury, giving Joachim Bjorklund the chance to stake a claim for a permanent first-team place.

Matt Piper, who has spent more time in the treatment room than on the pitch since joining Sunderland last year, faces a six-week lay-off with knee ligament damage. But Stephen Wright and Darren Williams could be fit to fill the right-back position at Derby.

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