A San Francisco judge acknowledged a pivotal California Supreme Court decision would affect the outcome of a closely watched labor fight between Grubhub Inc. and a former delivery driver but declined to say whether the decision should be applied retroactively, a key question that gig companies want answered.

Magistrate Judge Jacqueline Scott Corley of the U.S. District Court for the Northern District of California issued an opinion Wednesday in response to a question from plaintiffs attorneys who contend Grubhub is misclassifying its workers as contractors and not employees. Corley in February ruled for Grubhub, and the case, brought by a driver named Raef Lawson, is now pending before the U.S. Court of Appeals for the Ninth Circuit.

The distinction between independent contractors and employees—who are entitled to benefits, workers' compensation and other rights—is key in the mountain of lawsuits filed against gig companies with workforces made up largely of freelance workers who set their own schedules.