Scotland boss Frank Hadden will give Euan Murray and Nathan Hines until Friday to prove their fitness for their opening Six Nations fixture against Wales at Murrayfield on Sunday.

Murray, widely tipped as a potential British and Irish Lions prop, is the biggest doubt with a rib injury sustained during Northampton's European Challenge Cup win over Toulon two weeks ago. Hines meanwhile twisted his knee while playing for Perpignan against Stade Francais, and will be desperate to lend his weight to the Scottish effort. Both player shave been unable to train this week, leading to the Scotland camp extending the deadline for their fitness to Friday.

"We're still just monitoring Nathan and Euan," said forwards coach Mike Brewer I'd say Euan's probably a bit more doubtful than Nathan at the moment but we'll give them until Friday. They're very important members of the team, an integral part of our pack.

"We worked hard in the autumn as far as the tight five is concerned and losing two out of the five is a big part of our game so we're going to give them as long as we possibly can.

"We're trying to build a squad where no-one is bigger than the team and is doesn't matter if it's (captain) Mike Blair who's injured; we've got players who know the way we want to play, our systems and all the rest of it."

Should Murray fail to make the count then his place will likely be taken by uncapped Edinburgh prop Geoff Cross.

"Euan is a fantastic scrummager, he's very good in the collision, in the contact area, great body position, great leg power," said Brewer. "Geoff: a very good scrummager, scrummaged very well all year, scrummaged very well in the last Heineken Cup game against Leinster, against an Irish International but probably wouldn't have the experience.

"Geoff was a late starter to the game. They do have different attributes and it's the same as Nathan. Nathan's ability to offload in the close contact zone is quite different to that of any of other guys that may take his position. However, there are other areas of the game.

"For example, if you play Jason White in the second row, he's probably a better one-on-one defender than Nathan so strengths and weaknesses aren't what it's about. It's about balancing your side and having a profile in your pack both in attack and defence."

Flanker White has only just returned from injury but is being touted as a possible replacement for Hines despite his inexperience of playing at lock.

"Jason's a clever player. He knows how to manage his way through a game," said Brewer. "If he starts the game then he's the first one to put his hand up and say, 'Listen, bring somebody else on, they'll do a better job than me at the moment'.

"So I've got no concerns about that, he's a smart footballer, he's played a lot of rugby, and is very experienced. What he brings to the team as far as his leadership and his management of the team and on-field decisions far outweighs a possible lack of game time."