By Ronnie Cully and Thomas Jordan

OLD FIRM sharpshooters Scott McDonald and Kris Boyd will walk a title suspension tightrope in this weekend's derby collision at Ibrox.

Both hitmen are sitting on 15 disciplinary points and a yellow card would rule them out of the last day of the season fixtures on Sunday, May 24.

Boyd has been under threat of a one-game ban since he was cautioned at St Mirren on April 8, but the 30-goal striker has so far managed to stay out of trouble.

If, however, he is booked against Celtic then he would sit out Rangers trip to Dundee United on the last day.

McDonald has accumulated points at a rapid rate in the past few weeks after referee Dougie McDonald cautioned him in the back-to-back games against Aberdeen at Parkhead on April 18 and again at Pittodrie last Saturday.

Another booking on Saturday and the in-form Aussie would be missing when Hearts come to Parkhead on what could yet be a title-deciding day.

Celtic skipper Stephen McManus - who is stuggling to recover in time to play at Ibrox after limping off with a knee injury at Pittodrie - is also on the 15-point mark and one booking away from a ban, but he is now unlikely to feature.

Both managers were today beginning to piece together their teams ahead of what is a titanic encounter in terms of the destination of this season's title.

Celtic are already without the suspended Scott Brown, but boss Gordon Strachan hopes to have Georgios Samaras and Barry Robson available to him.

Rangers gaffer Walter Smith has been boosted by the news Sasa Papac is set to be fit after a knee problem.

The Bosnian defender is likely to return at left-back, leaving Stevie Smith to add some bite and dig in a midfield roles in front of him.

There is also a chance of Kirk Broadfoot making a surprise recovery from the foot problem that has side-lined for almost two months.

Smith, who also welcomes centre-half Madjid Bougherra back from suspension after he sat out Sunday's 2-0 win over Hearts, said: "Sasa has a chance of being fit.

"We thought he would be fit for the Hearts game, but just failed to make it so I imagine he'll be okay for the Old Firm game.

"Kirk is also back in training this week, but whether he will be ready for the game or not we will have to wait and see.

"It was also good to get Kyle Lafferty a run-out last weekend after five weeks out, so we have players coming back and that increases the options."