Washington Commanders backup quarterback Marcus Mariota suffers right-knee MCL sprain

A source familiar with the situation told one outlet that Marcus Mariota, the Washington Commanders' backup quarterback, suffered a sprain to the medial collateral ligament in his right knee during the preseason opener versus Miami. The injury is projected to keep him out of action for part of the regular season. The team has not publicly announced the injury, and coach Dan Quinn is scheduled to address the media later on Sunday.

In the same game, starter Jayden Daniels did not take the field, leaving the Commanders with only Sam Hartman and rookie Athan Kaliakmanis as remaining quarterbacks on the roster. The development raises questions about how the team will navigate the rest of training camp at the position. AP sports writer Stephen Whyno contributed to the report.