Adam Schefter of ESPN confirmed the diagnosis Monday, and the Seahawks are pursuing a reunion with running back Marshawn Lynch to help replace him.
Head coach Pete Carroll confirmed the talks with Lynch on Monday, adding the Seahawks are "going to give him a really good chance" to rejoin the franchise.
Carson took over as the starting running back in 2018 and proceeded to run for 1,151 yards and nine touchdowns in 14 games. He was 12th in DYAR (defense-adjusted yards above replacement) among running backs with at least 100 carries, per Football Outsiders.
This year, Carson finishes with 1,230 yards and seven touchdowns on the ground in 15 games.
Outside of selecting DK Metcalf in the second round of the draft, the Seahawks did little to upgrade the offense, largely due to the fact they didn't have much salary-cap space with which to make significant additions.
Carson's injury comes two weeks after Rashaad Penny suffered a season-ending torn ACL. C.J. Prosise injured his arm Sunday as well and will miss Week 17, leaving rookie Travis Homer as the top remaining option, leading to the talks with Lynch.