Source - Chargers rookie OT Joe Alt has sprained MCL - ESPN

Los Angeles Chargers rookie first-round pick Joe Alt sprained his MCL during Sunday's loss in Pittsburgh, a source told ESPN's Adam Schefter on Monday.

Alt is likely to be sidelined for Sunday's game against the Kansas City Chiefs before the Chargers go on their bye and then can reassess his injury.

Alt was one of several key Chargers players injured in Sunday's loss to the Steelers. Quarterback Justin Herbert aggravated his high right ankle sprain and left tackle Rashawn Slater sustained a pectoral injury.

Chargers coach Jim Harbaugh said Monday that X-rays on Herbert's ankle were negative. Harbaugh said he'd be able to give more specific updates on his injured players Wednesday.