Some reports in France stated that Russell was definitely out of the game but the news from the Scotland camp yesterday was not so definitive.
The 26-year-old rejoined the national squad yesterday and was said to be free of concussion symptoms. If that continues, he could yet play.
“There’s a minimum of six days and there is six days between then [Sunday’s game] and the [France] game,” said assistant coach Danny Wilson.
“But things need to go swimmingly well for that to happen. Those stages are dealt with by the medical staff.”
Russell was hurt by the knee of Toulouse winger Lucas Tauzin just before half-time of Racing’s Top 14 loss to Toulouse and stayed down for some time. He did not return after the break after failing the initial return-to-play test.
The potential loss of Russell would be another huge blow to Scotland, who carried a sizeable casualty list heading into the Guinness Six Nations. Others since injured include Stuart Hogg, WP Nel, Huw Jones and Ryan Wilson.
Head coach Gregor Townsend, pictured, yesterday called up Worcester stand-off Duncan Weir, Edinburgh trio Magnus Bradbury (back-row), Dougie Fife (wing) and James Johnstone (centre), and Glasgow’s Zander Fagerson (tighthead) and George Turner (hooker). Weir joins Pete Horne and Adam Hastings as an options at No 10.
Forwards coach Wilson said several eventualities will be taken into account this week as Scotland look to bounce back from the 22-13 home loss to Ireland with a first win in the French capital for 20 years.
Wilson said: “We’ve planned for such injuries during the game, before the game. Those things are covered. But the prep has to be adjusted if your 10 [stand-off] from the previous game isn’t available in the early part of the week.”
Asked if Russell would be given until the morning of the game to prove himself fit, Wilson replied: “Selection is not done yet. It’ll be completed after tomorrow’s training and we’ll know more in the next 24 to 48 hours. Tail-end of the week will determine what we can or can’t do.”
On Russell’s lack of symptoms, Wilson added: “It’s a really good thing. If he wasn’t symptom free today, that would be that. He is symptom free and he wouldn’t be here if he wasn’t, but there’s still a long way to go between now and Saturday.”