Source: Cowboys starting RT Terence Steele tears ACL, MCL 12:11 PM ET Todd ArcherESPN Staff Writer Close Covered NFL since 1997, Cowboys since 2003 Previously covered Bengals and Dolphins Lives in Dallas area with his wife and two children FRISCO, Texas -- The Dallas Cowboys ' fears Sunday night were confirmed Monday when an MRI showed right tackle Terence Steele suffered tears to the anterior cruciate and medial collateral ligaments in his left knee, according to a source. Steele was injured in the second quarter when a Houston Texans defender crashed into his leg while making a block. Steele started every game this season and 40 of 45 games in his career after joining the Cowboys as an undrafted free agent in 2020. He is the second starter the Cowboys have lost for the season in as many games with cornerback Anthony Brown suffering an Achilles tear against the Indianapolis Colts in Week 13. Editor's Picks Cowboys look to grow from slim win vs. Texans 15h Todd Archer 2 Related All-Pro right guard Zack Martin did not know the severity of the injury after the Cowboys' 27-23 victory over the Texans but said Steele has been their best lineman. "It's a big loss for us and we've got to find a way to rally and fill that spot for him because -- I said it last year and said it this year -- he's been our bellcow. So, we've got to step up and find a way to fill that hole." Josh Ball replaced Steele immediately in the Houston game, however, after two poor plays led to a Dak Prescott fumble and interception he was replaced by Jason Peters on the game-winning 98-yard drive. Peters had not played right tackle since early in his 18-year career with the Buffalo Bills . "I thought Jason really did a hell of job going in there and playing in that situation," coach Mike McCarthy said Sunday. "Jason's been in that 2-minute situation you know for a couple decades compared to Josh Ball. I think just the utilization of personnel was done very well." The Cowboys opened the 21-day practice window for Pro Bowl left tackle Tyron Smith last week and the hope is he could see some action this week against the Jacksonville Jaguars . Smith suffered a torn hamstring in training camp that required surgery. He said he felt, "great," after his first practice of the regular season. The Cowboys could go with a split at tackle between Ball and Peters, who is 40, but feel good about their depth. Steele is scheduled to be a restricted free agent after this season, and the Cowboys have hoped to sign him to a long-term deal.