Andy Webster has undergone further specialist tests to clarify when he will be able to play for Rangers as Walter Smith yesterday confirmed that two other Ibrox players face surgery.

Thomas Buffel has been ruled out for the remainder of the season after it was decided a persistent knee problem required an operation. It is possible the Belgian has played his last game for Rangers, given that a fee in the region of £1m was agreed with Hannover last month, only for the Germans to back out of the deal, claiming the demands from Buffel's camp had changed.

Steven Smith's future at Ibrox is far more assured, but he will be absent for at least the next month following hernia surgery. The 21-year-old left-back suffered a groin injury in the Old Firm match in December, leading to this attempt to restore him to fitness.

Webster has not featured for Rangers since joining on loan from Wigan Athletic until the end of the season. He suffered a medial ligament injury during his first Murray Park training session on January 6 and was initially expected to be out for six weeks. Further investigation is required, though, as the Scotland centre-back has not recovered as expected.

"Andy's recovery has been slower than anticipated so he's away to see a specialist," said Smith. "We're waiting on the report coming back from him.

"Steven needs a hernia operation and that will keep him out for four to six weeks. It's frustrating because the lad had a terrific start to the season. Steven was a player in my thoughts when I was Scotland manager because we only really had Gary Naysmith in that position. He was called up for one squad but was injured at the time."

The Ibrox manager insisted Buffel may yet resurrect his Rangers career. A fully-fit player would, though, also be more attractive to potential purchasers, with Smith admitting the knee problem was a factor in the collapse of Buffel's move to Hannover.

"When you get an offer for a player you accept it for different reasons, not necessarily because you don't think that player has a future at the club," said Smith "One of the reasons Thomas didn't go was because of this injury. It's something that has been troubling him for a while, although he has been able to train and play.

"We believe it's better he has this operation now, one of the benefits being that he'll be fit for the start of next season.

"The injuries are not great reading but we've had to do without these players since I arrived. It's disappointing but we'll get on with it."

There was more positive news about Dado Prso, who should recover from his hamstring injury towards the end of next week. The Croat is still pondering whether to retire at the end of the season because of a long-standing knee complaint, despite Ranko Stojic, who claims to represent Prso, saying earlier this week that the striker was ready to play on.

"The situation with Dado is clear," said Smith. "He is out with a hamstring injury and he has an ongoing knee problem that everyone knows about.

"His contract is up at the end of the season and at that time he'll look at the situation and decide whether or not he wants to play on or finish.

"As far as his hamstring goes, I would hope that by the time we get back from playing Hapoel Tel Aviv it would be more or less okay. If he's not fit for the Falkirk game next Saturday, then certainly for the return leg after that."

The looming resumption of UEFA Cup action is not deflecting Smith's attention from tomorrow's visit to face Kilmarnock at Rugby Park. Three clean sheets and seven points have been gathered from three matches since his return to Rangers, and a restoration of domestic pride remains paramount.

"The European game is a nice one for us but the priority is to finish as high as we can in the league," said Smith. "The international week gave us a bit of time to work on one or two things because it's been pretty hectic since we arrived.

"Rugby Park is always a difficult place to go and when you play against one of Jim Jefferies' teams you know it's going to be tough and competitive. That streak has been through all of Jim's teams and having just reached the League Cup final they'll obviously be confident."