Dallas Cowboys All-Pro guard Zack Martin suffered a hyperextended left knee during their preseason loss to the Cincinnati Bengals on Saturday, per Todd Archer of ESPN.

Archer also notes that Martin will undergo an MRI on Sunday to confirm the true extent of his injury.

Martin suffered the knee injury in the second quarter as Bengals cornerback Dre Kirkpatrick’s helmet hit Martin in the knee. Martin got up slowly and limped to the sideline. He did not return to the game.

After the game, Cowboys head coach Jason Garrett said the medical staff was “somewhat optimistic based on the initial observation” of Martin’s injury, while Cowboys owner Jerry Jones said he doesn’t think Martin’s situation is “problematic.”

Martin, who was the team's first-round pick in 2014, signed a massive six-year extension this offseason which made him the highest-paid interior offensive lineman in the league. He has been named as a Pro Bowler in each of his first seasons and has been a First-Team All-Pro twice. He has yet to miss a regular season game in his first four seasons, playing 64 out of a possible 64 games.

The Cowboys were already playing without starting center Travis Frederick against the Bengals after he suffered a series of stingers. Kadeem Edwards replaced Martin on Saturday after his injury.

The Cowboys will play their next preseason game on Aug. 26 against the Arizona Cardinals. But at this point, it seems highly unlikely that Martin will feature in that game as the Cowboys take extra precaution with him following his injury.