Gawker Media Group went on the auction block on Friday after filing for bankruptcy when a Florida judge upheld a $140 million jury judgment against it in a costly legal battle with former professional wrestler Hulk Hogan.

The company plans to sell its assets in bankruptcy court and has received an opening bid of $90 million from the digital-media company and magazine publisher Ziff Davis LLC, according to a person familiar with the matter.

The filing marks a stunning turn for a 14-year-old business that was a pioneer in online media when it was launched by entrepreneur Nick Denton. Its aggressive and sometimes lurid style of tabloid reporting made it an object of media fascination as well as ire among the enemies it made along the way.

A sale became inevitable after the judge overseeing an invasion-of-privacy case brought by Hulk Hogan—whose real name is Terry Bollea—declined to issue a stay pending Gawker’s appeal. That opened the door for Mr. Bollea to conceivably take control of the company. Mr. Bollea had sued after Gawker published a video of him having sex with the wife of a Florida radio shock jock.

Gawker Media’s bankruptcy filing blocks such a move, allowing it to continue operations while it seeks to raise cash for its appeals.