Ex-Munster and Ireland player currently plays for Sale Sharks
Former Ireland and Munster scrum half Peter Stringer faces up to three months on the sidelines after suffering an arm injury.
The Sale Sharks player has torn his bicep muscles, suffering the injury during a recent match against Worcester.
Sale director of rugby Steve Diamond confirmed that Stringer will be out of action.
"It's a blow for us as a club and for Strings but it offers an opportunity to James Mitchell to step up and be involved in the first team, in both the Premiership and the forthcoming European Champions Cup," he said.
Stringer, a 38-year-old veteran of 98 Ireland caps, was a regular for Sale in 2015-16 with more than 20 appearances.
In April, won the club's Player of the Season award.