Pressure had been building on underperforming Chargers coach Brandon Staley even before he oversaw a 27-point collapse in a stunning Wild Card loss on Saturday.
Lombardi and Day, who came in alongside Staley in 2021, have paid the price for that early exit, the team announced on Tuesday.
Led by Justin Herbert, the Chargers should have the talent to be a contender in the AFC, but the third-year quarterback is yet to win a playoff game.
Indeed, the Jaguars clash represented Herbert's postseason debut, and he looked to be on course for an impressive win after racing into a 27-0 lead.
But the Chargers added just three points in the second half as they lost 31-30, undone as so often by their subpar run game, which yielded only 20 yards and a single first down from eight carries after halftime.
That makes for an obvious area for improvement under the next OC, who will surely relish the opportunity to work with Herbert.