Cleveland legend Bernie Kosar was booted from his radio gig with the Browns on Sunday ... and it's all because the ex-quarterback bet on his former team to beat the Steelers.
Kosar -- who played for the Orange and Brown from 1985-93 -- placed the $19,000 wager (in honor of his jersey number) with the Tipico Sportsbook app last weekend ... becoming one of the first legal bets placed in Ohio.
The former Pro Bowler claimed if Cleveland (+120 in most sportsbooks) ended up beating Pittsburgh, he would donate the winnings to charity.
The Browns ended up losing, 28-14, but not only did Kosar lose his $19k ... he also lost his pregame radio show job with the team -- due to breaking one of the league's most unforgivable rules.
"Earlier this week we notified Bernie, that per league policy, we were required to remove him from our pregame radio coverage for the season finale after he violated the NFL gambling policy by placing a bet on an NFL game," the Browns said on Sunday.
"We understand what Bernie means to this community and our history but as team contracted personnel hired to provide content on our media platforms, his bet was a violation of NFL rules and we must adhere to all NFL policy."
Kosar addressed the move on Twitter ... saying, "I am shocked & disappointed. Brown & Orange is my life … Go #Browns."
Kosar isn't the only one in the Browns organization getting the boot on Sunday -- the team also canned defensive coordinator Joe Woods after the season finale.