PITTSBURGH -- The Pittsburgh Steelers acquired Joe Schobert from the Jacksonville Jaguars in a Thursday night trade, a source confirmed to ESPN's Michael DiRocco, filling a significant need at inside linebacker with a month until the season opener.

Terms of the trade, including the Steelers' return package to the Jaguars, were not immediately disclosed.

The Steelers needed inside linebacker depth after the surprise retirement of veteran Vince Williams on the eve of training camp, leaving former top-10 pick Devin Bush, who tore his left ACL last season, and Robert Spillane as the starting inside linebackers. The rest of the group included Ulysees Gilbert III, safety-turned-linebacker Marcus Allen and 2021 fourth-round pick Buddy Johnson.

"We've got to see what's going on there," defensive coordinator Keith Butler said of the inside linebackers last week. "We've got to find out who's going to be our best backups. Right now, that's still in question, I think."

Spillane proved to be a solid replacement for Bush last season, displaying his strength as a run-stopper. But the Steelers' inside linebackers have shown a weakness in coverage throughout training camp, and Schobert is especially strong in coverage. His addition will allow the Steelers to rotate Spillane and Schobert to play alongside Bush.

"Great place to play behind that D-line," Schobert told ESPN's Jeremy Fowler.

The Jaguars signed Schobert, 27, to a five-year, $53.7 million contract with $21.5 million guaranteed in March 2020 to play middle linebacker in a 4-3 defense. The Steelers have just more than $12 million in salary-cap space, giving them plenty of room to absorb Schobert's $7 million salary this season.

He had 141 tackles, 2.5 sacks and three interceptions in his only season with the Jaguars. The Jaguars signed former Kansas City and Dallas linebacker Damien Wilson in April, and he had been splitting first-team reps with Schobert at middle linebacker throughout training camp in new coordinator Joe Cullen's 3-4 defense.

Wilson is a stronger run-defender than Schobert, who is better in coverage. Per ESPN Stats & Information research, Schobert is one of only 14 players who have at least two interceptions, two sacks and two forced fumbles in consecutive seasons dating to 1994, when forced fumble data began being accurately kept. That list includes Hall of Famers Brian Dawkins, Ray Lewis and Charles Woodson and another player -- Julius Peppers -- who will become eligible for the Hall of Fame in 2024.

Over the past two seasons, Schobert has seven interceptions, 4.5 sacks and four forced fumbles.

The NFL Network first reported about the trade.