BALTIMORE — After the Ravens’ second possession, Casey Hayward went to the sideline with newfound confidence. He had been a little skeptical when, the Monday before, coaches told the defense in the week’s first meeting about a secret plan to slow the bruising Baltimore offense that ground them up two weeks earlier.



To overcome a thin linebacking corps stressed by Jatavis Brown’s season-ending ankle injury the week before, coaches tweaked the defense. In practice, they used seven defensive backs to equal the speed of Lamar Jackson, the Ravens’ shifty quarterback. The idea was radical: No NFL team this season had used seven defensive backs more than 18 times in a game, and the Chargers had only used the personnel in 50 snaps all season total (five percent).



Hayward wasn’t stunned by the switch — the Chargers sometimes used seven defensive backs at the end of last season — but he was surprised they would try it against this...