Gloucester scrum-half Haydn Thomas will be out for six weeks after fracturing his collarbone in the European Challenge Cup win over Bayonne. The 23-year-old, who had made 11 appearances this season, was on as a replacement when he was injured.
"It's disappointing because he had been pushing for an opportunity," coach Dean Ryan told the club website.
"With the Six Nations upon us he had a real chance to press that claim but unfortunately that won't happen now."
Gloucester's two other first choice scrum-halves, Peter Richards and Simon Amor, are away this week with the England senior and sevens squads respectively.
But they hope to have Richards back in the fold in time for the Premiership game with London Irish on Saturday.