"It's gonna change because he's not there," defensive coordinator Teryl Austin said Thursday. "Obviously, everybody knows what he does really well, which is a lot of things, but I think structurally we're gonna remain the same.
"We're gonna do the things that we think are good, that are sound fundamentally. ... We know we may not get the type of production T.J. had, but if we get good, solid varsity players, we're gonna be fine."
The Steelers officially placed Watt on injured reserve earlier Thursday morning, ruling him out for at least four games.
Watt, the reigning NFL Defensive Player of the Year, tore a pectoral muscle in the final seconds of regulation in the Steelers' Week 1 win over the Cincinnati Bengals on Sunday. But Watt won't require surgery, a source told ESPN's Adam Schefter, and he could return in about six weeks.
"Obviously, you don't want to play without a guy like that, but guys gotta step up," defensive captain Cameron Heyward said of Watt. "We're not reinventing the wheel. We're not going out there saying that we have to change up our entire scheme and stuff, but we just gotta make sure we do our jobs."
In a corresponding move, the Steelers signed outside linebacker David Anenih to the 53-man roster off the Tennessee Titans' practice squad. Anenih signed as an undrafted free agent in May and finished the preseason with three sacks. The Steelers also signed former Washington Commanders linebacker Ryan Anderson, an Alabama product, to the practice squad.
"I don't know that any of us are shocked by the performance," Steelers coach Mike Tomlin said of Highsmith. "As a matter of fact, I think most of us expect it to continue. You're not going to get three sacks each and every week, but he's a good player and he's a man to be reckoned with for sure."
The Steelers will also use outside linebacker Malik Reed, whom they acquired in a trade before the season, and Jamir Jones, who was recently picked up off waivers, to help fill Watt's extended absence. Reed played over 700 snaps in each of the past two seasons with the Denver Broncos and racked up 13 total sacks.
"I think we can get pressure," Austin said. "I'm not sure you can ever say you get as much [without Watt], but I'm not gonna discount anything. I think we got quality guys. The guys behind him had sacks in this league. We've got good guys inside. I think Alex is coming along. So I think there's ways to generate pressure and generate sacks."