The Chargers are in last place and virtually everyone believes it's a foregone conclusion head coach Brandon Staley will lose his job ... and that'd be a mistake, according to Antonio Gates, one of the greatest players in franchise history.

TMZ Sports ran into the 8x Pro Bowler earlier this week in L.A., who spent all of his 16 seasons as a pro with the Bolts, and asked him whether it was time Staley got the ol' heave-ho after another disappointing season in SoCal.

"Ya know, I don't personally think [the coach should be fired]," AG told us.

The Hall of Fame candidate explained his reasoning ... "Just because of the relationship he has with the players. I'm big on, 'Can you get the guys to play for you?' I feel like Staley has a rapport with the players, and I believe in that particularly because I've been in that locker room."

Staley's been the HC since the 2021 season ... and while the squad is chock full of talent, including star QB Justin Herbert, the team has struggled to find any postseason success. Last season the 10-win Chargers lost to the upstart Jacksonville Jaguars in the Wild Card round, and this year has been a disaster.

Things have been so bad for the 4-7 squad, there's near-constant talk about who could replace Staley after his all-but-guaranteed demise ... and Bill Belichick is often at the top of the list.

Things aren't exactly going smoothly for the 6x Super Bowl-winning head coach (8 total) on the other coast, either. Bill and owner Robert Kraft have reportedly had tension, and it's not crazy to think Belichick walks away or even gets fired after the 2023 season.

We asked Gates if he believed Belichick would be a good fit in Los Angeles.

"I think Belichick is a proven, historical winner. Why wouldn't he be good for any team? I don't know how the old-school coaching would transition now. I come from that old-school mentality, but I don't know if these guys can commit to that style of play. I'm not sure. I don't know.

"But we do know what we know is that he's a proven winner. I just don't know if his style of play is still considered valuable in the National Football League."

The Chargers have 6 games remaining … including a matchup with the Pats this Sunday.