Gloucester stand-off Danny Cipriani has been ruled out for up to eight weeks with a torn calf muscle.

Head coach Johan Ackermann says he must choose from Owen Williams and Lloyd Evans as a replacement for the 16-times capped England number 10 for Sunday's Champions Cup trip to Toulouse.

"It's not nice to lose any player to injury. Especially a quality player like Danny," said Ackermann.

"But we couldn't have asked for better timing in terms of Owen's return."

Ackermann told BBC Radio Gloucester: "We've also got a lot of faith in Lloyd. He's been the understudy and patiently waited for his chance and has learned a lot from Danny.

"I could have picked him at any time over the last few months. The two of them can hopefully carry on keeping the attack going and scoring tries for us."

Gloucester wing Charlie Sharples has also been ruled out for "a couple of weeks to three months" following a knee operation.

Ackermann also faces the potential loss next month of exciting teenage wing Louis Rees-Zammit, who has been called up at the age of 18 alongside Williams for Wayne Pivac's first Wales Six Nations squad.

"It's going to be challenging for us going forward with our preparation but I'm always telling our players you have to grab opportunities when they come in life," Ackermann added.

"You have to grab them when you have the chance and I'm delighted for Louis. he has grabbed that opportunity well.

"But I'm also delighted for Owen. After a long time out to get a call-up. He is extremely professional and keeps himself in the best possible. He will get better as the weeks go past "

Gloucester go to Toulouse second in European Champions Cup pool knowing that they must beat the unbeaten pool leaders to have a chance of going through with the French side.

The Cherry and Whites kept their hopes alive with last weekend's 29-6 bonus-point victory over Montpellier.

Despite losing Cipriani after just 12 minutes, Williams came on to help Gloucester stay in contention for one of the three best runner-up spots thanks to tries from Willi Heinz, Rees-Zammit, Ben Morgan and Todd Gleave.