France's Coly returns to Montpellier after thigh injury
Montpellier's Coly was expected to be a back-up to captain Antoine Dupont for France's tournament opener in Italy on February 5.
The uncapped 23-year-old will be out for at least a month and will also be unavailable for the match against Ireland in Dublin on February 11.
He could return against Scotland on February 26 in Paris.
"A little tear to put an end to my time (with France)," Coly said on Instagram.
"Time for recovery," he added.
Coly is one of 14 players from the 42-man squad to return to their clubs but he will miss his outfit's trip to league leaders Toulouse on Sunday.
Winger Matthis Lebel and flanker Francois Cros, who play for the side at the top of the table, are also among those made available for their clubs this weekend.
Racing 92's Nolann Le Garrec is the other scrum-half in Fabien Galthie's set-up with regulars Maxime Lucu and Baptiste Couilloud already sidelined.
In other injury news for Galthie, tight-head prop Uini Atonio sat out training on Wednesday for a second straight day with a knee problem.
Galthie, who will lead hosts France at this year's Rugby World Cup, is set to name his matchday squad for the Italy game on February 3.