"First of all, let’s not put the words fitness and Ben Roethlisberger together, they are allergic to each other."
That's Jay Glazer keeping it ALL THE WAY real about Big Ben's offseason workout routines ... and it's pretty savage/hilarious.
The NFL insider was filling out a mailbag piece for The Athletic this week ... when one fan asked about the Steelers QB and a return to "85% plus fitness" after arm surgery.
Glazer's response?
"There is no fitness in Ben Roethlisberger."
Ouch.