Olympic champion Andy Murray will begin his Tokyo campaign against ninth-seeded Canadian Felix Auger-Aliassime.
The Briton won back-to-back gold medals at London 2012 and Rio 2016 but has twice required hip surgery since and is currently ranked 104th in the world.
World number 15 Auger-Aliassime reached the quarter-finals at Wimbledon this month, knocking out fourth seed Alexander Zverev in the last 16.
Murray lost to the 20-year-old in straight sets at the US Open in 2020.
Former world number one Murray won consecutive matches at a Grand Slam for the first time in four years when he reached the third round at this year's Wimbledon.