Arsenal defender Kieran Gibbs will be sidelined for up to five weeks after undergoing hernia surgery on Thursday.
Fellow full-back Carl Jenkinson is also set for a lay-off after suffering a stress fracture in his back.
But there was better news for the Gunners as midfielder Abou Diaby returned to training after a five-month absence following an ankle operation.
Meanwhile midfielder Jack Wilshere is off crutches for the first time since ankle surgery in September.
Manager Arsene Wenger also revealed striker Marouane Chamakh will be available for Saturday's trip to Norwich but 18-year-old forward Ryo Miyaichi will be out for four to six weeks with an ankle sprain.
"We have had some bad news because we have lost two full-backs over the [international] break," Wenger said.
"At first he [Gibbs] had an abdominal strain - certainly caused by the fact he had a hernia already.
"When the strain was healed we discovered he had a hernia. We had a fear that could be behind it so we decided to do the surgery."
Gibbs has been Wenger's preferred option at left-back this season following Gael Clichy's summer departure to Manchester City.
And 19-year-old Jenkinson has also forced his way into the first team since France defender Bacary Sagna broke his leg in October.
"Carl has a stress fracture in his back," Wenger added. "We found a small stress fracture that we noticed at an early stage.
"If he continued to play it could have got worse and then he could be out for a long time. At the moment the specialist has decided to rest him."
Wenger will be boosted by Diaby's return, although he is unlikely to risk the 25-year-old this weekend.
Diaby has made 123 appearances since arriving from Auxerre in January 2006 but he has not featured in the Premier League this season.
"Diaby has been out for four or five months so he will need some adaptation," Wenger said.
Fellow midfielder Wilshere is unlikely to return until the new year but the 19-year-old tweeted: "First day without crutches in a while! Feels so good!"
Arsenal have only won once away from home this season but they go to Carrow Road in search of their fifth straight Premier League victory.