Scotland scrum-half Chris Cusiter is refusing to take his selection for granted in next month's RBS 6 Nations curtain-raiser against England at Twickenham - even if he does regain fitness in time.
Cusiter knows Mike Blair, Scotland's only other frontline number nine, will not be available for the match on February 3 - having injured his shoulder earlier this month.
A tourist with the British and Irish Lions in 2005, Cusiter has been one of Scotland's key performers in recent seasons but has not played since dislocating his shoulder against the Pacific Islanders on November 18.
That lack of match practice may prove decisive when national coach Frank Hadden has to choose his scrum-half.
Cusiter said: "To play for Scotland in the Six Nations is the main reason I play rugby - but to come back after two-and-a-half months out injured and go straight into those sorts of matches is a big 'ask'.
"I'll just have to see how it goes.
"It's difficult to say when exactly I'll be back. From a structural point of view the joint is fairly sound, but I only started doing rugby training last week."
Cusiter is therefore remaining necessarily cautious.
"I'm hoping to build it up so that I am doing 'contact' at some point either this week or next week, so we'll have to wait and see how it reacts to that.
"Whether I can get back on to the pitch with the Border Reivers before the Six Nations kicks off is going to be an important factor.
"Time is not really on my side, but if the joint is structurally sound and I'm feeling good then I hope I will be in the frame."
Cusiter will clearly not be fit this weekend, meaning that the Reivers' match against Newport Gwent Dragons in the Celtic League a week on Friday will be his first and last opportunity to prove his fitness.
If Cusiter does not make it in time then Rory Lawson is favourite to start in his place against England.
He made his international debut from the bench against Australia in November and has been in fine form for Gloucester in recent weeks.
Hadden's other option is Sam Pinder, who was capped twice during last summer's tour of South Africa and has been training with the national squad this week.
Cusiter added: "I don't know what is going to happen in the Six Nations - if someone else is given a shot then it will make things interesting.
"It will be up to me and Mike to win our places back."