Play video content EXCLUSIVE TMZSports.com

Herschel Walker says he's paying the price for supporting Donald Trump -- telling TMZ Sports he's been dropped from multiple speaking engagements for publicly backing the GOP candidate.

Walker was one of Trump's first big celebrity endorsers -- praising his former "Celebrity Apprentice" boss as a brilliant man who will truly make America great again.

But after he went public, Walker says he started getting axed from speaking gigs -- most recently getting canceled from an event in California because organizers were afraid Walker would attract anti-Trump protesters.

Walker wouldn't name the groups who 86'd him -- but says it's happened at least 3 times in various states.

In fact, he spoke about the situation this week on the "TMZ Sports" TV show on FS1.