John Travolta bald drink tennis towel

John Travolta has been busy filming the stoner flick Savages opposite the gorgeous Blake Lively ... so we understand the A-list actor needs a break.

Travolta, who's going without a hair piece for his current role, hit the courts with a friend in Calabasas for a relaxing game of tennis. Gotta stay hydrated!

The 57-year-old actor is probably still wondering who ripped off his vintage Mercedes over the weekend. The Mercedes-Benz 280SL, worth at least $100,000, is still missing ... and Santa Monica P.D. tells us there are still no leads.

At least you got tennis, John ... to work off that stress and those pounds!