Week 4 preparation brings out the chess match mentality in NFL coaches, and San Francisco 49ers defensive coordinator Robert Saleh knows he’s facing a particularly crafty opponent this weekend.

The Jacksonville Jaguars have developed something that’s making defensive coordinators across the league take extra notes during film study.

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Saleh pointed out that Jacksonville’s offense, under head coach Liam Coen with help from former Minnesota Vikings assistants, has built what he calls a sophisticated signal-stealing system.

It’s completely legal, but that doesn’t make it any less challenging to handle.

“Liam (Coen) and his staff, a couple of guys coming from Minnesota, they’ve got, legally, a really advanced signal-stealing type system. Where they always find a way to put themselves in an advantageous situation. They do a great job with it. They formation you, to try to find any nugget they can. So we’ve got to be great with our signals, and we’ve got to be great with our communication to combat some of the tells that we might give on the field,” Saleh explained during Thursday’s media session.

Robert Saleh says the Jaguars offense has a signal stealing system that’s legal:

“Liam Coen and his staff coming from Minnesota they got legally a really advanced signal stealing system where they always find a way to put themselves in an advantageous situation. They do a great… pic.twitter.com/XVJfPKhL2y

— Coach Yac 🗣 (@Coach_Yac) September 25, 2025

The 49ers’ defensive coordinator makes it clear this isn’t about breaking rules. Jacksonville’s approach involves studying every detail from formations to hand signals, turning basic defensive tendencies into valuable intelligence.

Even with careful preparation, Saleh admits the Jaguars can still catch teams off guard.

He emphasized that execution and fundamental play become critical when facing this kind of systematic approach. Saleh recalls similar challenges when his team faced Minnesota last year, noting how impressive Jacksonville’s study habits and timing appear on film.

Jacksonville Jaguars head coach Liam Coen greets quarterback Trevor Lawrence (16) after the game of an NFL football matchup at EverBank Stadium, Sunday, Sept. 21, 2025, in Jacksonville, Fla. The Jaguars defeated the Texans 17-10.

This meticulous system reflects Jacksonville’s broader effort to reassert itself as a rising power in the AFC South. Their young roster loaded with developing talent, combined with Coen’s influence and his staff’s collective knowledge, has been evident through the early weeks of the season.

Smart preparation meets legal gamesmanship, and the Jaguars are making everyone else work harder because of it.

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