Steelers quarterback Russell Wilson was limited at Thursday's practice due to calf tightness, three days before Pittsburgh's Sept. 8 season opener against the Atlanta Falcons.

Head coach Mike Tomlin told reporters the tightness was in the same right calf that Wilson strained at the start of training camp in July. He said that Wilson would likely undergo further evaluation "to exercise an abundance of precaution."

Asked if backup Justin Fields would be ready to go against the Falcons in the event that Wilson can't play, Tomlin expressed confidence.

"I'm extremely comfortable if that is the case, certainly," Tomlin said.

Wilson did not address reporters. He was initially scheduled for media availability Thursday, but that was pushed back to Friday.

Who will start in Week 1?

Wilson and Fields both joined the Steelers this offseason after Pittsburgh parted with 2022 first-round pick Kenny Pickett. Theirs was one of the most intriguing quarterback battles of the preseason after both arrived having started for their previous teams.

Wilson, 35, is a former Pro Bowler who won a Super Bowl with the Seattle Seahawks before struggling in two years as a starter with the Denver Broncos. Fields, 25, started for three seasons with the Chicago Bears after they selected him in the first round of the 2021 NFL Draft. The Bears traded Fields to the Steelers in the offseason prior to selecting quarterback Caleb Williams with the No. 1 pick in April's draft.

Tomlin said in March that Wilson was in "pole position" for the starting job, but that there would be an open competition between the two quarterbacks. Tomlin waited until the completion of training camp and the Steelers preseason to name Wilson as the team's starter on Aug. 28. Days later, Wilson's teammates voted him as a team captain.

Now, three days before the season opener, Wilson's availability for Sunday is in doubt, raising the prospect that Fields could be Pittsburgh's Week 1 starter.