Based on the wiki, there's no exact timeline given for Mariota's current knee issue. He aggravated his right MCL during Week 4's London game vs. Indianapolis and did not return — rookie Athan Kaliakmanis took over and is expected to start going forward (from the Marcus Mariota page).
The key facts:
- August: Suffered a right MCL sprain in the preseason opener; was expected back for the regular-season opener.
- Week 4 (Oct 4): Aggravated that MCL, ruled out of the game, with rookie Athan Kaliakmanis stepping in.
- No return timetable has been reported in the wiki yet.
The wiki notes this is his second MCL issue on the same knee this season, and with Jayden Daniels also sidelined, the Commanders are down to rookie Kaliakmanis under center. For fantasy purposes, Mariota is not startable until we hear a recovery timeline.