London - England and Gloucester flyhalf Danny Cipriani will be sidelined for up to six weeks after suffering a "small tear" to a chest muscle, the Premiership club said on Wednesday.
Cipriani sustained the injury during his club's 29-17 Heineken Champions Cup defeat to Exeter last week.
The 31-year-old, signed from Wasps earlier this year, has been instrumental for Gloucester in the first half of the season, helping them to third place in the Premiership.
His injury setback also deals a blow to his hopes of being included in Eddie Jones's England squad for the 2019 Six Nations, which starts on February 1.
"He's got a small tear in the muscle in his pectoral, so he's going to be out for anything from four to six weeks," Gloucester head coach Johan Ackermann told Gloucester Live.
"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."
Gloucester also lost Italy international Jake Polledri to injury on December 8.
According to Gloucester Live, the flanker will undergo an ankle operation and is set to miss 10 to 12 weeks.