An already problematic Jaguars injury situation has become a season-ending problem.

Jaguars starting left tackle Anton Harrison has a torn right ACL, according to NFL Network, in a huge blow for the defending AFC South champions.

Harrison had already been placed on injured reserve after suffering the injury in Week 5, but arthroscopic surgery Thursday revealed that he had torn the ligament, per ESPN.

The 2023 first-round pick suffered the injury during the team’s 19-17 win in London over the Eagles, reportedly during a running play.

He ultimately would be carted off the field.

The Jaguars placed him on injured reserve, which carries a minimum of a four-week absence, on Oct. 13.

“We’ll just figure it out when we get back,” Jaguars coach Liam Coen said on Oct. 14 about the injury. “When we get back he’ll have a little procedure, see what it looks like in there. Don’t have any new news on what it could really look like until we get in there. So, we’ll just take it day by day.”

That procedure showed that Harrison would not be able to return this season, and it’s a huge blow for one of the AFC’s contenders since its tough to replace such a premium position midseason.

Harrison, 24, moved this offseason from right tackle to left to protect Trevor Lawrence’s blindside, and ranked 30th among eligible tackles, according to Pro Football Focus’ rankings.

He graded out as a better run blocker than pass protector.

While this is a tough break for both the player and the team, he at least has a contract for 2027 after the team picked up his fifth-year option in April.

Walker Little replaced him for the 34-31 Week 6 loss to the Texans, and Jacksonville (4-2) is off this week before returning in Week 8 at home against a Colts team that just fired general manager Chris Ballard.

“I have a lot of confidence in Walker and Cole (Van Lanen) to go in there,” Coen said last week of handling Harrison’s absence. “Next-man-up mentality.”