BALTIMORE -- Baltimore Ravens left tackle Ronnie Stanley suffered a serious left ankle injury late in the first quarter of Sunday's 28-24 loss to the Pittsburgh Steelers and will miss the rest of the season.

The All-Pro was carted off the field just two days after he signed a five-year, $98.75 million extension.

In the final minute of the first quarter, Steelers linebacker T.J. Watt inadvertently rolled into the back of Stanley's lower left leg while trying to sack quarterback Lamar Jackson. Stanley, 26, appeared to be in a lot of pain, pounding his fist on the ground.

Stanley had his left leg placed in an air cast. As Stanley was helped into the cart, the entire Ravens team swarmed around him in support.

Baltimore is now without two starting offensive linemen: Stanley and right guard Tyre Phillips, who left Sunday's game earlier with an ankle injury and was later ruled out. The Ravens have had to juggle the offensive line, moving Orlando Brown from right to left tackle and inserting Patrick Mekari (right guard) and D.J. Fluker (right tackle) off the bench.

Jackson faced a lot of pressure from the Steelers, who sacked him on three of his 12 dropbacks in the first quarter.