ATLANTA — Justin Fields started at quarterback for the Pittsburgh Steelers in Sunday’s season opener against the Atlanta Falcons while Russell Wilson is sidelined with a calf injury.

Wilson, who was limited to Thursday and Friday practices after aggravating an injury he suffered during training camp, is the Steelers’ emergency quarterback, meaning he can play only if Fields and Kyle Allen, who will serve as a reserve on Sunday, are injured.

Wilson took the field just before 10:30 a.m. ET on Sunday and threw with a pair of Steelers equipment workers for about 15 minutes. Wilson appeared to move slowly through the warmup, as he took several small dropbacks before firing a pass. He warmed up in each end zone, finishing with fades to the corner.

Wilson returned to the field just after 11:00 a.m. ET and spoke briefly with general manager Omar Khan. Wilson resumed throwing, this time to quarterbacks coach Tom Arth. Fields warmed up nearby, throwing the ball to tight end Connor Heyward and wide receiver Calvin Austin III. Wilson continued to move minimally through warmups, while Fields repeated rollouts and dropbacks.

Both Wilson and Fields threw passes to wide receivers as they lined up for routes during warmups, but Fields took the first reps of the drill each time, followed by Allen and then Wilson.

Fields started 38 games in his three-year stint with the Chicago Bears before being traded to the Steelers for a conditional sixth-round pick in 2025 during the offseason. The sixth-round pick will become a fourth if Fields plays more than 50 percent of the team’s snaps this season.

Fields is 10-28 in those 38 starts with the Bears, throwing for 6,674 yards with 40 touchdowns and 30 interceptions. He also has rushed for 2,220 yards and 14 TDs.