The Chargers organization was given the first option to join the Rams after a year (if they failed to reach a new stadium deal with the city of San Diego); the Chargers exercised this option on January 12, 2017, making Los Angeles home to two NFL franchises again. (Had the Chargers declined to exercise this option, then the Raiders would have had this option.) The Raiders eventually relocated to Las Vegas, Nevada, after 25 years back in Oakland. The Rams were the second team to relocate to a previous home city (after the Raiders, who left Oakland after the 1981 season and moved back in time for the 1995 season).
