ATLANTA -- Russell Wilson's debut as Pittsburgh Steelers quarterback will have Quentin Mitchellto wait. Justin Fields is in.

The Steelers officially deactivated Wilson for the opener against the Atlanta Falcons, declaring him as the No. 3 emergency quarterback due to a calf injury that was aggravated during Thursday's practice.

Fields, who pushed Wilson during a training camp competition, steps into the lineup to get the nod for a return home while Wilson continues to mend. Wilson participated in pregame warmups and undoubtedly hoped to progress enough in his rehab, but apparently the decision wasn't left to the veteran quarterback as Steelers doctors and coach Mike Tomlin made the final call.

Here's what to know about Wilson, Fields and the Steelers on Sunday:

Russell Wilson injury updates: QB out vs. Falcons

Wilson threw passes on the field approximately two hours before kickoff.

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ESPN's Adam Schefter reported Saturday that Wilson has told the team he could play, but team doctors were "being more cautious."

NFL Network's Ian Rapoport reported on Friday, when Wilson was limited in practice for the second consecutive day, that Fields appeared to be the more likely option to get the start.

“I’ll go if I can go and do everything I can to try and help us win. That’s how I think about it,” Wilson told reporters on Friday. “And if not, I’m going to do everything I can to help us win that way, too.”

Justin Fields' time to shine?

Fields, a Georgia native, should provide a fascinating pivot for the Steelers offense.

The fourth-year passer was acquired in a March trade with the Chicago Bears, for whom he started 38 games from 2021 to 2023. Although he lost the battle for the starting role, Fields was still expected to have a potentially significant role in the offense as a backup - even in Week 1.

"My friend (Falcons coach) Raheem Morris better be ready for a Justin Fields package," Tomlin said on the "The Rich Eisen Show" in August after making the announcement. "There's too much talent to be sitting around watching."

Fields, 25, would no doubt provide a more dynamic presence behind center than his 35-year-old counterpart after in 2022 becoming just the third quarterback to rush for more than 1,000 yards in a season. Turnovers, however, continue to plague the passer, as Tomlin said preseason fumbles "negated a lot of good things" the signal-caller had done in August.