In 1973, Leonard would return to Vel's Parnelli Jones, driving the #1 Samsonite Parnelli VPJ-2-Offenhauser. The season would be a struggle for Leonard as he could only get a best finish of 5th place at the season-opening Texas 200 at Texas World Speedway and the second heat of the Trentonian 300 at Trenton International Speedway. At the Indianapolis 500, Leonard would struggle to qualify after teammates Andretti and Unser qualified 6th and 8th. He would eventually qualify in 29th place and finish in 18th place due to a broken hub. Leonard would finish out the season 15th in points.