ASHBURN, Va. — The Washington Commanders put Marcus Mariota on injured reserve on Saturday, ensuring the veteran quarterback will miss at least the first four games of the season.

Coach Dan Quinn said Mariota strained a pectoral muscle. The 30-year-old Mariota missed practice this week and was listed with a chest injury.

Journeyman Jeff Driskel is expected to back up Jayden Daniels in the season opener Sunday at Tampa Bay. The Commanders signed former Notre Dame and Wake Forest QB Sam Hartman off their practice squad and elevated defensive tackle Sheldon Day and linebacker Nick Bellore to the active roster for their game against the Buccaneers.

Rookie defensive tackle Johnny Newton is doubtful as he rehabs from offseason foot surgery.

Washington signed Mariota to a one-year, $6 million contract before selecting Daniels with the second pick in the draft. The 2015 No. 2 pick said at the time he was willing to serve as a mentor or start, as needed.

— The Associated Press