Jay Glazer -- Mike Shanahan WANTS TO GET FIRED ... That's Why He Benched RG3

Redskins head coach Mike Shanahan benched Robert Griffin III because HE WANTS TO GET FIRED ... this according to the ultimate NFL insider Jay Glazer.

Shanahan is set to make $7 MILLION next year ... and Glazer says if the team gives Mike the ax, they're gonna have to pay him.

Which is why Jay, who was leaving the gym in Bev Hills yesterday, was so adamant that Mike is doing everything in his power to force the Redskins front office to fire his ass ... starting with sending RG3 to the bench.

The math is simple -- millions of dollars for doing absolutely nothing.

But Jay says Mike's gotta be careful, because there's still a chance the plan could backfire.