Philip Rivers just turned 36 in December, and even though Anthony Lynn said the quarterback could play into his 40s, the Chargers have to start planning for the future at some point. Could this be the year they draft Rivers’ future replacement? “Everybody’s in play for us,” Lynn said. “We’re trying to get better — not just quarterback, every position.” The Chargers have yet to address the future at the position. Los Angeles had Kellen Clemens and Cardale Jones behind Rivers last season. Clemens becomes a free agent later this month, and Jones has played in only one game, with 11 pass attempts, in his two seasons.