(Photo credit: Kyle Terada-Imagn Images)

Previously unbeaten San Francisco's loss to Jacksonville on Sunday included a heated exchange after the game between 49ers defensive coordinator Robert Saleh and Jaguars head coach Liam Coen, who had to be separated.

Saleh had raised Coen's ire on Thursday when he remarked about the Jaguars coaches being adept at 'legally' stealing opponents' signs, which he framed as a compliment. Coen didn't take it as such and apparently let Saleh know after Jacksonville's 26-21 win over the 49ers in Santa Clara, Calif.

Saleh was restrained by a Niners staff member, and Coen by Jaguars offensive lineman Robert Hainsey, according to multiple reports of the midfield encounter when coaches and players from both teams more typically exchange pleasantries and congratulations.

'Not a big deal,' Coen, a first-year head coach whose team is 3-1, told reporters after the game. 'I'm just going to keep that between us right now. That's it.'

Saleh, a former New York Jets head coach and longtime NFL assistant, was not available to media after the game.

San Francisco head coach Kyle Shanahan, whose squad fell to 3-1, had said on Friday that Saleh was praising the Jaguars' ability to pick up on opponents' signs. He said on Sunday that he didn't see their Sunday meeting.

'I don't think you should be that sensitive about it, but it is what it is,' Shanahan said. 'I'm not too worried about it.'

Shanahan said his organization doesn't care if Saleh's comments upset the Jaguars' coaching staff.

'It has no effect on the game,' Shanahan said. 'I think Saleh was paying them a big compliment in what they're good at doing. It's not illegal. He said (there is) nothing illegal about it. I think you use the word sign stealing and what the headlines get with those type of words, I think the perception of that becomes wrong.'

The origin of the comments goes back to when Saleh was asked on Thursday about the main challenge for the 49ers' defense against the Jaguars.

'They've got, legally, a really advance signal-stealing type of system where they always find a way to put themselves in an advantageous situation,' Saleh said Thursday. 'They do a great job with it.'

Saleh traced Coen's coaching history with Los Angeles Rams head coach Sean McVay, and Jaguars offensive coordinator Grant Udinski's time coaching under Minnesota Vikings head coach Kevin O'Connell. Both McVay and O'Connell have worked with Shanahan or in his systems.

--Field Level Media