Whites head coach Marcelo Bielsa is also "waiting for news" about centre-back Pontus Jansson after a recent back problem.
Cooper pulled his hamstring during the warm-up before Tuesday night's Championship encounter at Swansea City and United have stated that the 26-year-old is likely to be sidelined for between two and three weeks.
Northern Ireland international Dallas has returned to training after his recent quad injury but Bielsa has revealed the winger will not feature in Saturday's clash at Carrow Road in addition to midfielder Forshaw who is still recovering from damage to ligaments in his foot.
Swedish international Jansson has returned to training after a recent back injury which forced the centre-back to miss Tuesday's trip to Swansea though Bielsa is still waiting to see if the 27-year-old will be able to face the Canaries.
"Cooper won't be able to play, neither Dallas, neither Forshaw" said Bielsa, asked about his latest team news.
"We are waiting for more news regarding Jansson. We will see if he can play or not."