Flowers was concussed in a collision with Chiefs running back Jamaal Charles on Sunday. Charles told ESPN Radio on Wednesday that he saw "light bulbs" after the hit. Charles stayed in the game and was not diagnosed with a concussion, while Flowers was taken out and did not return.
Four Chargers are listed as out for Thursday's game. Along with Flowers, they include linebacker Manti Te'o, and running backs Donald Brown and Ryan Mathews. Cornerback Jason Verrett is listed as questionable with a shoulder injury.
Richard Marshall, a 29-year-old veteran, is listed as Flowers' backup.
Flowers had started six of San Diego's seven games this season. He missed the team's Week 2 game against the Seahawks after injuring his groin in practice.
Flowers signed a one-year deal with the Chargers last offseason, after spending six years with the Chiefs.
- Dan Gartland