Retired French tennis star Caroline Garcia says she rejected a $270,000 sponsorship from a betting company for her podcast because of cyberbullying from gamblers. She didn’t mention Dave Portnoy, but the Barstool founder proved her point when he called for the “murder” of Las Vegas Raiders coach Pete Carroll after losing a bet over the weekend.

“Prison Pete Carroll. Murder Pete Carroll,” Mr. Portnoy screamed in a video posted on X. “I want Pete Carroll murdered.”

Mr. Portnoy went apoplectic after the Raiders kicked a 46-yard field goal on the last play of the game in Denver’s 24-17 victory at Allegiant Stadium on Sunday. The Broncos entered the game as a 7.5 point favorite, meaning those betting on Denver lost their money because of the field goal. Mr. Portnoy said the ending cost him $250,000.

Though Mr. Portnoy later apologized for his rant, saying “I disavow real violence,” his viral post calling for Mr. Carroll to be “murdered” over an outcome of a football game is an example of the type of cyber abuse Ms. Garcia says athletes, including tennis players, have been dealing with some the widespread legalization of sports wagering. It’s the primary reason she turned down a sponsorship offer from an undisclosed betting company, she says.

“Over the past two years of interviewing players, coaches, agents and parents, one theme keeps coming back again and again,” Ms. Garcia posted on X. “Betting has become one of the biggest sources of pressure, abuse, and hate in  modern sport. Every player, from Top 10 stars to ITF grinders, has stories. DMs (direct messages) full of insults after a match. People demanding money back because they lost a bet. Even death threats. Not because of sport. Because of gambling.”

Ms. Garcia, who once ranked as high as No. 4 in the world, launched her podcast “Tennis Insider Club” after retiring last year following a 14-year career. She said she’s not “judging” anyone who bets casually or other athletes who accept betting sponsors. Her podcast, she said, is focused on growing tennis in a way that is healthy for athletes and fans. “Taking betting money would move us in the opposite direction,” she said.

Mr. Portnoy, who often posts videos about sports betting, has 3.7 million followers on X and appears on his own podcast “Wake Up Barstool.”  He said his outburst on the Raiders was an emotional reaction to losing his bet.

“I would like to say this loudly, clearly, emphatically, we never want physical harm to anybody based on a decision, a play, anything,” he said on his podcast Monday. “However, in the moment, you may be upset by one of the wildest sequences that cost you a quarter million. So it is a metaphorical murder.”

He added: “Anybody who thought I was actually calling for him to be murdered and killed so he couldn’t breathe … you misread the situation, and I apologize.”

While kicking a field goal on the final play of a game a team is going to lose sounds questionable, the tactic wasn’t without merit. Mr. Carroll’s job isn’t to monitor point spreads, but to win games.

Down 10 in the closing seconds, the Raiders, trailing 24-14, needed a field goal and touchdown to tie the game and force overtime. The Raiders were hoping there would be enough seconds remaining after making the field to potentially recover an onside kick and throw a long pass into the endzone for a game-tying touchdown. In a season where little has gone right for Mr. Carroll and the Raiders (2-11), it didn’t work.

While Mr. Portnoy posted his viral rage on social media, it’s the hundreds if not thousands of faceless abusers with anonymous accounts that concern Mr. Garcia. She first brought attention to the problem of cyberbullying by people who bet on tennis matches during the U.S. Open last year

“Maybe you can think that it doesn’t hurt us, but it does. We’re human,” she said at the time. “Sometimes, when we receive messages, we are already emotionally destroyed after a tough loss. And they can be damaging. Many before me have raised the subject. And still no progress has been made.”

Ms. Garcia suggested those who engage in cyberbullying online should face legal consequences. “Why online, we are free to do anything,” she said. “Shouldn’t we reconsider anonymity online?”

Ms. Garcia’s stance is admirable, but far from the norm. Sports betting fueled by sports betting apps is part of broadcasts, team partnerships, promotional codes and celebrity endorsements these days. Plenty of fans bet responsibly. Some, however, who lose make it too personal.

“We will find partners who want to grow with us,” Ms. Garcia said, “not exploit the pressure athletes already face.”