The Biggest Decision Chargers DC Chris O'Leary Got Wrong Against Cardinals, Next Move

The Los Angeles Chargers have plenty to fix going forward following their loss to the Arizona Cardinals. Sunday's game was a debut for both of the Chargers' new coordinators and marked the NFL play-calling debut for defensive coordinator Chris O'Leary.

Chris O'Leary was hired to return to the Chargers franchise after one year away at Western Michigan, to take over defensive coordinator duties from his mentor Jesse Minter. Upon his arrival, O'Leary promised to do two things, evolve and elevate the defense that was already in place.

This offseason, the buzz around the defense and the word continuously used was aggression. Jesse Minter, as a play caller blitzed at one of the lowest rates in the NFL with the Chargers in 2024 and 2025. Minter's units were complex in disguises but conceptually consistent to get offenses into known passing situations on third down.

O' Leary's coaching background, specifically his ties to Notre Dame, led to an assumption that he would blitz more. In his regular season play calling debut, he did the exact opposite. His mentor and the Baltimore Ravens blitzed at a 43 percent rate compared to O'Leary and the Chargers sitting only at 20 percent.

Every NFL defensive play caller ranked by blitz rate in Week 1:

Brian Flores: 82.1%
Dan Quinn: 50.9%
Aaron Glenn: 44.9%
Jesse Minter: 43.4%
Kelvin Sheppard: 43.0%
Todd Bowles: 42.9%
Lou Anarumo: 39.1%
Mike Macdonald: 35.8%
Vic Fangio: 35.8%
Christian Parker: 35.3%
Zak Kuhr:…
— Ryan Paganetti (@RyanPaganetti) September 14, 2026

The Chargers defense eventually settled down as the game progressed but they struggled to get off the field yielding 23 first downs. Cardinals quarterback Jacoby Brissett masterfully got rid of the ball in lightning time, with the third-fastest time to throw in the first week of NFL action behind only Patrick Mahomes and Joe Burrow, according to Next Gen stats.

What doomed the Chargers was the lack of communication amongst the defensive backs as they attempted to disguise coverages to slow down Brissett's processing. The Cardinals mercilessly attacked the middle of the field and most of his attempts were under ten yards. Brissett finished with an average depth of target of 8.2 yards.

There are a handful of methods to slow down a quick passing attack and traditional pass rush is not one of them. The Chargers edge rushers did not stand a chance against the ball getting out so quickly. Disguise and route disruption is another method to slow down the passing attack. With coverage disguises causing more confusion than they seemed to help, O'Leary shifted to blitzing a bit more and leaving cornerback Cam Hart and Derwin James in key man to man matchups.

The defense ultimately gathered their bearings and stopped the Cardinals offense. The Chargers offense faltered and couldn't capitalize in time. When Arizona blocked a punt and recovered at the three-yard line, there wasn't much the defense could do.

Starting with softer coverage allowed the Cardinals to attack underneath and keep drives moving. O'Leary could not find the correct dials to disrupt the defense until later in the game. The Chargers will be facing another quarterback capable of attacking underneath and the middle of the field this week in the Las Vegas Raiders and Kirk Cousins. The plan to slow down the quick passing game needs to be dialed in this week.

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