So says coach Mike McCarthy.
McCarthy declined to elaborate on the injury, but did say it was "a little more serious" than the team initially thought.
Morency was hurt in the Packers' first practice on Saturday and the injury was described as a bruised knee yesterday.
Morency opened camp as the team's top running back in a group that includes rookie Brandon Jackson as well as P.J. Pope and Noah Herron.
Morency gained 421 yards in 96 carries last season as Ahman Green's backup.
He also missed two games with a lower back injury.
Green signed with Houston in the off-season.