With the visiting Broncos trying to continue their pursuit of a playoff bye, the Steelers look to solidify their place in the AFC wild-card race Sunday with their 10th consecutive victory in December.
Manning returned to practice this week for the first time since he was pulled from a 29-13 home loss to Kansas City on Nov. 15 because of a torn plantar fascia in his left foot. Coach Gary Kubiak, however, said the 14-time Pro Bowler won't be available Sunday.
After winning his first three starts, Osweiler completed 35 of 51 passes for a career-high 308 yards in last Sunday's 15-12 home loss to Oakland. The fourth-year pro was sacked five times, including one for a safety, and didn't throw a touchdown pass for the first time in five games.
Kubiak wouldn't say whether Osweiler has a chance to keep the job. Denver is 7-2 under Manning, though the veteran leads the league with 17 interceptions after throwing four while posting a career-worst 0.0 passer rating in his last game against the Chiefs.
"Whatever happens in the future happens in the future," Osweiler said. "That really doesn't pertain to me right now. That's out of my control. What I can control is my preparation this week for the Steelers, and that's where my focus is."
The Broncos sit one game behind New England for the AFC's top seed and are tied with Cincinnati for second, but they don't hold the tiebreaker against either team.
Denver (10-3) certainly didn't do Osweiler any favors last weekend when tight end Vernon Davis and star wideout Demaryius Thomas dropped passes at key times. Former Steelers receiver Emmanuel Sanders also muffed a punt at his own 11-yard line without being hit.
"It's a done deal. We watched the film, turned the page and now it's over," defensive back Chris Harris said. "Now we're just focused on Pittsburgh and what we have to do to get this win. It's a pivotal game for us to bounce back. I think that we can do it."
Pittsburgh has been tough against the run, ranking sixth while giving up 88.3 yards per game. The Steelers have been vulnerable against the pass and rank 31st with an average of 279.0 allowed.
Sanders rubbed some of his former teammates the wrong way after signing with Denver prior to last season when he said he never met a quarterback who prepared like Manning. Sanders, however, insisted the statement was not an intended jab at Roethlisberger.
"I've got nothing but love for Big Ben," he said.
The Steelers (8-5) have to love the way they've been playing on offense after scoring 30 or more points in a franchise-record five consecutive games. They've averaged 494.0 yards while winning four of those to move into a tie with Kansas City and the New York Jets for the top wild-card spot.
"We feel like as long as we're winning, everything is going to take care of itself," linebacker Arthur Moats said.
Roethlisberger has been impressive during this stretch with 363.0 yards per game with 10 touchdowns and five interceptions. The three-time Pro Bowler completed 30 of 39 passes for 282 yards and one pick in last Sunday's 33-20 win at first-place Cincinnati.
Antonio Brown has 48 receptions for 679 yards and four scores over his last five games. He had seven catches for 87 yards last Sunday in the Steelers' ninth straight win in December, which ties with Carolina for the longest active streak.
"We just know it's that time of year," Roethlisberger said. "It's crunch time and you've got to get hot at the right time."
Extending that run won't be easy against Denver, which leads the NFL in sacks (44), total defense (272.5) and defensive scoring (17.3). The Broncos had three sacks last weekend while limiting Oakland to 126 yards - the fewest they've given up since 2012.
Denver has won 12 of the past 17 meetings, including the playoffs.