Tests on Bud Dupree's left knee have confirmed a torn ACL, ending the Pittsburgh Steelers outside linebacker's season, a source confirmed to ESPN.

Dupree appeared to injure his knee on a noncontact play in the second half of Wednesday's 19-14 victory over the Baltimore Ravens.

Playing on the one-year franchise tag, Dupree will be a free agent after this season. He followed up his breakout 2019 campaign with another strong effort this season, recording eight sacks, two forced fumbles and 26 tackles. Along with T.J. Watt, Dupree was a foundational member of the Steelers' pass rush.

Steelers tight end Eric Ebron tweeted well-wishes to Dupree on Thursday, writing that he was "heavy hearted, but I know u will attack rehab/treatment and be back 100x better."

love my brudda ?? heavy hearted, but I know u will attack rehab/treatment and be back 100x better. @Bud_Dupree pic.twitter.com/cxIABkDanb

— Eric Ebron (@Ebron85) December 3, 2020

Replacing Dupree won't be easy. Rookie Alex Highsmith, the Steelers' third-round draft pick, is the top candidate to fill his role.

Dupree is the second Steelers defensive starter to go down with such an injury. Middle linebacker Devin Bush tore his ACL against the Cleveland Browns in Week 6.

News of Dupree's test results was first reported by NFL Network.