Jason Kelce's back with the Eagles ... and he celebrated his return in the most Kelce way possible -- by rippin' a massive shot with Philadelphia's general manager!!
The All-Pro -- and noted party animal -- made it known on Monday morning he was coming back for his 13th NFL season ... saying in a statement, "I ain’t f***ing done yet!"
A short time later, he revealed how he informed Howie Roseman of his decision ... and, yes, it featured plenty of booze.
Roseman, after giving the 35-year-old a big hug, poured Philly's center a shot cup of mezcal before giving himself one too .