PITTSBURGH - For the third week in a row, the Pittsburgh Steelers are readying for Justin Fields to start at quarterback Sunday as Russell Wilson continues to work through a lingering calf injury.

"We're kind of in the same posture as we were in last week with Russ," Tomlin said Tuesday. "As I sit here today, Russ is not scheduled to be a full participant in practice [Wednesday], and so we're ready in a plan that features Justin and his readiness."

Wilson was a limited participant in each practice last week and was inactive as he served as the emergency third quarterback in the win against the Broncos.

Wilson, who initially injured his calf on the eve of training camp as he pushed a sled in a team conditioning test, hasn't fully participated in practice or played in the first two regular season games since aggravating his calf on Sept. 5.

"We'll follow Russ throughout the week, and if his participation gets to a level in participation and quality where we should consider him, we'll delve into that at that time and obviously when that happens is a component of the consideration," Tomlin said.

"But as I sit here today, he is not scheduled to be a full participant tomorrow in practice and so we're readying ourselves around Justin and we'll stay in that mindset until something else happens. Hypotheticals is a waste of our time now."

In Wilson's place, Fields and the offense helped the Steelers to a 2-0 start on the road, something the team hasn't accomplished since 1999. Though the offense has only scored one touchdown in two games - a pass from Fields to tight end Darnell Washington - Fields has been largely efficient, completing a career-high 69.8% of passes. He also hasn't thrown an interception or lost a fumble.

"It's been really good," Tomlin said of Fields' decision-making, "but I expect it to be."

Fields, though, will face his toughest test to date on Sunday against an Los Angeles Chargers team that's allowed just 6.5 points per game, the fewest in the league through two weeks. The Steelers defense is second at 8.0 points per game.

In working with Fields in-game, Tomlin said his relationship with the quarterback has grown and he's learned about how Fields leads and deals with adversity.

"It just grows in in-game environments," Tomlin said of his relationship with Fields. "There was some point in the game. I went up to him, I told him to challenge his unit in terms of cleaning up their plays so we could get out of the stadium and end the game. I asked him to do it in his own voice, in his own words, but those are some of the things that you ask a quarterback to do."

But Tomlin shut down speculation about what Fields' performances could mean for the starting quarterback position long-term, emphasizing he won't make a determination about the job until Wilson returns from the calf injury. Wilson was still listed as the starting quarterback in the most recent depth chart released Tuesday, while Fields remained second.

"My position regarding the pecking order and the depth chart has not changed guys," Tomlin said. "And it won't until the other guy gets healthy and then we'll give it real consideration. Until then, I won't speculate. I don't know how many ways I can tell you guys that."