Justin Fields operated the Pittsburgh Steelers’ offense for most of Thursday’s practice with starter Russell Wilson limited because of calf tightness, the same injury that kept him out of several days of training camp.

Head coach Mike Tomlin said there are no long-term concerns about Wilson’s health. Pittsburgh opens the regular season Sunday at Atlanta.

“We wanted to exercise some precaution,” Tomlin said, “and see what tomorrow looks like and kind of go from there.”

Tomlin said a medical evaluation would take place “out of an abundance of caution” on Friday but otherwise downplayed the injury.

“It really doesn’t” impact game planning, Tomlin said, adding “I’m extremely comfortable” if Fields is forced into action.

Expect skepticism from the Falcons. Last week, Tomlin warned Falcons head coach and former Buccaneers co-worker Raheem Morris he should “be prepared for Justin Fields.”

Morris thanked Tomlin, apparently in jest, on Wednesday for forcing him to waste time looking at how the Steelers used Fields.

Wilson is a nine-time Pro Bowl selection with the Seattle Seahawks who was released by the Denver Broncos in March. Tomlin named Wilson the team’s starter following the final preseason game last month.

Wide receiver Van Jefferson said both quarterbacks are capable of winning at Atlanta.

“Obviously Russ is a great competitor and wants to be out there. If Justin has to step out there, I think he’s more than prepared to do that,” he said.