The hits just keep on coming for the Seahawks defensively.

As reported by Ian Rapoport of NFL Network, Seattle fears starting linebacker Mychal Kendricks tore his ACL during Sunday's 26-21 loss to San Francisco. He will undergo an MRI on Monday to confirm the diagnosis.

Kendricks hobbled off the field midway through the third quarter after chasing down 49ers fullback Kyle Juszczyk on a 49-yard reception. He was listed as questionable, but did not return.

Seattle has relied heavily on its 4-3 base defense with Kendricks, Bobby Wagner, and K.J. Wright on the field together. According to Pro Football Focus, the Seahawks used base personnel on 68.3 percent of snaps during the first 15 games of the season, nearly 30 percent more than any other team.

Assuming Kendricks needs knee surgery, rookie Cody Barton will replace him in the starting lineup. The third-round pick out of Utah filled in admirably for Kendricks in two starts against the Rams and Panthers earlier this month, but didn't necessarily draw good reviews from coach Pete Carroll after Sunday's loss.

"Yeah, he did alright," Carroll bluntly said. "He missed some - he missed a couple things. He’s a great kid. He’s going to be a great football player for us."

While Barton has shown plenty of upside in limited playing time, it'll be interesting to see if Seattle deploys more nickel packages with five defensive backs on the field against the Eagles next Sunday.

Kendricks finished his second season as a Seahawk with 71 tackles, fourth on the team behind Wagner, Wright, and cornerback Tre Flowers. He will be an unrestricted free agent in March and still faces sentencing for insider trading charges in February, casting doubt on whether or not he'll be back in 2020.