COSTA MESA, Calif. -- Los Angeles Chargers coach Anthony Lynn said Monday that quarterback Philip Rivers is in the NFL's concussion protocol from a head injury sustained during the team's 20-17 loss to the Jacksonville Jaguars on Sunday.
"Phil came in today and self-reported concussion symptoms," Lynn told reporters. "He's seen our doctors and been evaluated. And he's now in the concussion protocol. And we'll evaluate him for the rest of the week."
Rivers, who turns 36 in December, has been one of the most durable quarterbacks in NFL history. He has not missed a start since taking over as the Chargers' starting quarterback in 2006, a stretch of 194 straight games -- the second-longest active streak behind New York Giants quarterback Eli Manning (220).
The North Carolina State product famously played with a torn ACL in the AFC Championship Game against the New England Patriots following the 2007 regular season.
Rivers also played through a chest injury and a bulging disk in his back during the 2014 season.
Through nine games this season, Rivers has completed 60 percent of his passes for 2,263 yards with 15 touchdowns and seven interceptions.
Tight end Antonio Gates has played with Rivers since 2006 and understands the veteran quarterback's competitive nature.
"It's so early right now to try and make speculations on whether or not he'll be ready to go," Gates said. "But you know how this league is. To be honest with you, I don't even really have an experience with him not being out there.
"Fortunately, I'm pretty sure they'll go through the right steps in the protocols to try to get him back on the field. But as of right now, his health is probably the main concern, to make sure he's OK to play, I think. That's speaking from a personal standpoint as a friend, just making sure he's healthy enough to go out and play and help us win."
Clemens, 34, has served as Rivers' backup since 2014 and has an 8-13 career record as a starter. Clemens made his last start for the Los Angeles Rams when they were in St. Louis, a 27-9 loss to the Seattle Seahawks in the final game of the 2013 season.
"I have complete faith in Kellen," guard Kenny Wiggins said. "I mean, he's what, an 11-, 12-year pro? He has starting experience and knows the offense as well as anybody."