As season approaches, Mike Tomlin keeping plans flexible for some Steelers' defensive starters

Mike Tomlin’s initial depth chart of the regular season lists no definitive defensive starters at inside linebacker or strong safety. The same could be said at slot corner even though Chandon Sullivan is listed ahead of Elijah Riley.
The Pittsburgh Steelers coach isn’t trying his hand at gamesmanship ahead of the team’s season-opening game Sunday against the San Francisco 49ers at Acrisure Stadium.
His starters — as well as the rotation that follows — at those positions will be based on matchups depending on how the 49ers utilize their star offensive players.
“Flexibility from a matchup perspective is really in vogue in today’s game defensively,” Tomlin said Tuesday at his weekly news conference. “If you’re going to be excellent on defense, you better be mindful of matchups.”
And so it is that the Steelers will open the season by taking a collaborative approach in replacing Terrell Edmunds at free safety, the three inside linebackers either released or let go in free agency and the two primary slot cornerbacks who now draw a paycheck elsewhere.
“We have quality depth and capable people,” Tomlin said. “Not only this week, but week in and week out, we’ll be willing to mix and match in an effort to get the appropriate matchups and the best mix of people on the field.”
At strong safety, free-agent acquisition Keanu Neal and a re-signed Damontae Kazee are listed as the co-starters on the depth chart. Neal, who has reached triple digits in tackles three times in his seven NFL seasons, could be used as an extra defender in the box against 49ers running back Christian McCaffrey.
Kazee could be used in pass coverage when the Steelers go to a three-safety package as they try to contain Deebo Samuel, who, like McCaffrey, is a dual-purpose threat.
Cole Holcomb and Elandon Roberts are listed as the starters at inside linebacker, although Kwon Alexander is considered a co-starter at both spots. Holcomb was signed to be a three-down player and is viewed as the best option for defending a running back or tight end, such as the 49ers’ George Kittle, over the middle.
As for the slot cornerback position, Sullivan’s snaps as a starter might depend on how frequently Patrick Peterson lines up outside.
The Steelers experimented with using Peterson in the slot during training camp as a way to get second-round pick Joey Porter Jr. on the field. Riley is another option as is the recently signed Desmond King.
Tomlin is used to mixing and matching on defense. Last year, the Steelers had 16 starting combinations over 17 games, and they used 447 combinations of lineups over 1,063 defensive snaps.
No matter who is on the field Sunday against the 49ers, Tomlin said one characteristic must be established if the Steelers are going to beat a team that reached the NFC championship game a year ago.
“We better tackle well,” he said. “We better be sound schematically in terms of some of the matchup-related things. We can’t put people in bad circumstances athletically.”
That is no easy feat considering the playmakers surrounding 49ers quarterback Brock Purdy, who, like the Steelers’ Kenny Pickett, is in his second NFL season and first as a full-time starter.
A year after averaging an NFL-high 18.2 yards per catch and totaling 1,770 yards from scrimmage, Samuel had his role reduced after the McCaffrey acquisition in midseason, and Brandon Aiyuk emerged as a receiving threat with 79 catches for 1,015 yards.
McCaffrey played his first injury-free season in three years and totaled 1,139 yards rushing and 741 receiving on 85 catches to go with 13 combined touchdowns. At tight end, Kittle had 60 catches for 765 yards and 11 touchdowns.
Tomlin said the 49ers might have the best trio of “one-on-one space winners” in the NFL at their respective positions.
“The people you put on them are significant,” Tomlin said. “That is going to be our story.”
Joe Rutter is a Tribune-Review staff writer. You can contact Joe by email at jrutter@triblive.com or via Twitter .