Bundee Aki is in a race to be fit for Connacht's crunch PRO14 tie against Munster on Saturday.
The Ireland centre is struggling with a knee injury, and will be monitored throughout the week before a final decision on his fitness is made.
With Ireland due to begin their Six Nations campaign against Wales in just under five weeks, Andy Farrell will also be sweating over the fitness of Aki.
Connacht head coach Andy Friend is hoping his talisman will be able to feature at the Sportsground this weekend, but he didn't sound overly optimistic.
"It's to be determined yet," Friend said. "Bundee has got a knee injury which we're working through. We've got a few other blokes who, as is the case at the moment, it's day-by-day where you're checking on their availability. Hopefully we'll get a couple more back but we'll wait and see."
Tom Daly is poised to continue in Connacht's midfield and after his outstanding display in last week's shock win over Leinster, Friend knows he can rely on him.
Connacht are aiming to back up their victory at the RDS with another important win against Conference leaders Munster.
• France have reached an agreement with clubs that means the internal politics that undermined their chances of winning the Autumn Nations Cup have been resolved for the Six Nations.
Over 25 first-choice players were unavailable for the climax to the autumn against England on December 6 due to the Top 14's opposition to an extended international window.
Head coach Fabien Galthie could only pick each player a maximum of three times across the six Tests and, having front-loaded his stars at the start of the competition, he fielded a shadow side at Twickenham that went down fighting 22-19.
But a deal has been struck for the Six Nations that gives Galthie access to all players for the five game weeks and a training camp.