Patton originally had surgery for a broken fifth metatarsal on July 4 after slipping on a wet floor during a workout. The procedure on Wednesday was to "encourage further healing," the team said in a statement.
No timetable was given for his return.
He has played in just one game for the Timberwolves this season, logging four minutes and scoring a basket in a blowout loss to Utah on April 1. He has appeared in 38 games for the Timberwolves' G League affiliate in Iowa.
The Timberwolves acquired Patton, the 16th overall pick in the 2017 draft, as part of the trade with the Bulls that brought Jimmy Butler to Minnesota.