The 25-year-old German appeared in the Diriyah Tennis Cup exhibition tournament in Saudi Arabia where he defeated Austria's Dominic Thiem in two super tiebreaks.
World number 12 Zverev then lost to the Russian Daniil Medvedev, 6-4, 6-0.
Olympic champion Zverev left Court Philippe Chatrier at the French Open in June in a wheelchair, subsequently undergoing surgery to repair torn ligaments in his right ankle.
He subsequently missed Wimbledon and the US Open.
A planned return at the Davis Cup in September came up short when Zverev pulled out after experiencing "extreme pain".