A component of Gawker Media’s liquidation plan that writers and editors were told would protect them from future lawsuits can’t stop a Las Vegas oddsmaker’s defamation case against a freelance journalist who wrote a Deadspin article critical of betting advice on his website, a judge ruled Friday.

Judge Stuart Bernstein of the U.S. Bankruptcy Court in New York denied a request by journalist Ryan Goldberg to enjoin a lawsuit brought last year by oddsmaker RJ Bell and his betting site, Pregame. The lawsuit claims the Deadspin...