The Steelers are hoping Isaac Redman runs all over the Broncos on Sunday night. (US Presswire)

Steelers vs. Broncos -- Week 1

Where: Sports Authority Field at Mile High, Denver (grass, outdoors)

When: Sunday, 8:20 p.m. ET (NBC)

Spread: Broncos by 2

Forecast: Unseasonably warm, kickoff temperature in the low 80s, no rain forecasted.

2011 records: Steelers (12-4); Broncos (8-8)

Past results: The Tim Tebow-led Denver Broncos beat the Pittsburgh Steelers 29-23 in overtime in a wild-card playoff game Jan. 8. Two most recent regular-season meetings -- Nov. 9, 2009: Steelers 28, Broncos 10; October 21, 2007: Broncos 31, Steelers 28. Series record: Broncos hold a 13-7-1 edge.

What matters: It was the most recent time the Steelers played a meaningful game, but a lot has changed since WR Demaryius Thomas took overtime's first play from scrimmage 80 yards for a touchdown off a pass from Tebow on Jan. 8. Tebow, of course, is gone, traded to the New York Jets. Veteran QB Peyton Manning, of course, is in. Also, the Steelers had a string of high-profile retirements, including WR Hines Ward, DL Aaron Smith, DL Chris Hoke and LB James Farrior. Sunday also will feature an entirely new coordinator matchup when Pittsburgh has the ball. The Steelers brought in OC Todd Haley to replace Bruce Arians, and the Broncos hired former Jaguars coach Jack Del Rio to replace Dennis Allen as defensive coordinator.

Who matters: LB Chris Carter apparently will start at outside linebacker in place of LB James Harrison if, as expected, Harrison can't play. Carter, drafted last year out of Fresno State, appeared in eight games last season. He might have been in a battle just to make the team entering camp, but injuries to Harrison and LB Jason Worilds had him running with the first team the entire preseason. At what is a glamour position in the Steelers' defense, it will be interesting to see if Carter can be a playmaker.

Key matchups: The Steelers' rebuilt (again) offensive line goes against what is one of the top defensive fronts in the NFL. LB Von Miller and DE Elvis Dumervil combined for 21 sacks last season, and second-round pick DE Derek Wolfe has impressed enough he's listed atop the depth chart. The Steelers moved OL Willie Colon to left guard this season, but he has played in only one NFL game since 2009. LT Max Starks is coming off ACL surgery, and RG Ramon Foster is stepping in for rookie first-round pick David DeCastro.

Injuries of note: Harrison's left knee and RB Rashard Mendenhall's right knee apparently will keep them out of the game. Harrison did not practice Thursday or Friday and reported soreness. He referred to himself as a game-time decision and is listed as questionable, but players who do not practice late in the week are historically extremely unlikely to play for the Steelers. Mendenhall practiced fully this week -- his first time on the practice field since tearing his ACL on Jan. 1. He has not been ruled out but is listed as doubtful, and it would be shocking if he played. DeCastro is out for several more weeks with a knee injury.

Inside stuff: Expect a running back-by-committee approach, something the Steelers never embraced under Arians. Haley has a past with the concept, and RBs Isaac Redman and Jonathan Dwyer on Friday both referenced that as the plan. Redman, who purportedly tops the depth chart after Mendenhall, has dealt with ankle and hip/groin injuries all preseason. Dwyer opened the eyes of coaches and fans with an impressive training camp.

Connections: Thomas and Dwyer were two high-profile weapons at Georgia Tech from 2007-09. ... CB Keenan Lewis, making his first start as an official starter for the Steelers, is from New Orleans. He'll try to defend and/or intercept passes from Manning, also a New Orleans native.

Stat you should know: Last season, the Steelers led the NFL in passing defense, and the Broncos ranked second-to-last in passing offense. The Manning-for-Tebow tradeoff just might change that, though.

Record watch: TE Heath Miller needs 56 receiving yards to move into ninth place on the Steelers' career list. QB Ben Roethlisberger needs 10 completions to reach 2,100 for his career.

Looking ahead: Incredibly, the Steelers play only one intradivisional game before the week of Thanksgiving. With some potentially tricky games coming up against the Jets at home next week, at Oakland on Sept. 23 and hosting Philadelphia on Oct. 7 following a bye, the Steelers can't afford to get into too big of a division hole before the games against the Bengals and Ravens commence.

Prediction: Broncos 24, Steelers 20

Follow Steelers reporter Chris Adamski on Twitter @CBSSportsNFLPIT and @BuzzsawPGH.