Walker rode the "Fast & Furious" franchise to fame, starring in all but one of the six action blockbusters, beginning with the first film in 2001.
He had been on break from shooting the seventh installment; production began in September and while much of the film has been shot, it's incomplete.
Universal Pictures has not said what it plans to do with "Fast & Furious 7," which currently is slated for release in July.
