Stephens was only in the starting line-up at Barnsley on Saturday as captain Johnnie Jackson is out with a calf strain.
But the 25-year-old had to go off at half-time after suffering a groin injury.
Happily for Powell Stephens' replacement, youngster Jordan Cousins, scored on his Championship debut as the Addicks came from behind to draw 2-2.
"It was an enforced change with Dale Stephens picking up a groin injury," said Powell.
"I've got trust in my young players and in Jordan, who has done extremely well this pre-season. That's why he's in the squad and that's why I brought him on.
"He repaid us with a goal and a real steadying performance."