LeSean McCoy just shaded the hell outta Dak Prescott ... calling the Dallas Cowboys quarterback "ass" and claiming he's playing like "trash" after a loss to the Jacksonville Jaguars.
The ex-Philadelphia Eagles star unloaded on Dak during his appearance on FS1's "Speak" this week ... bluntly saying #4 is not living up to expectations as the leader of America's Team, and certainly not playing like a man deserving of a 4-year, $160 million contract.
"Dak is ass," McCoy said. "Can I say that on TV? 'Cause he is ass ass.