England fly-half Danny Cipriani will be sidelined for up to six weeks after suffering a “small tear” to a chest muscle.
Cipriani sustained the injury during his club’s 29-17 European Champions Cup defeat to English Premiership rivals Exeter on Friday.
It deals a blow to his hopes of being included in Eddie Jones’ England squad for the 2019 Six Nations, which starts on February 1.
The 31-year-old, signed from Wasps earlier this year, has been instrumental for Gloucester in the first half of the season.
“He’s got a small tear in the muscle in his pectoral, so he’s going to be out anything from four to six weeks,” Gloucester head coach Johan Ackermann said.
“Obviously he’s been part of every game this season and played a lot of those games 80 minutes, so it is a big challenge now for us to get through this block without him.”