It's the end of an era ... Kenny Mayne announced he's leaving ESPN after an epic 27 year run.
"I am leaving ESPN," Mayne tweeted Monday ... "Salary cap casualty."
61-year-old Mayne -- who started at ESPN in 1994 -- thanked former ESPN execs Vince Doria and Al Jaffe for helping him get hired back in the day ... and also praised the current staff.
"I will miss the people. I will miss the vending machine set up over by the old [Scott Van Pelt] joint. We had everything.