Lewis, 34, signed with the Mavericks on a one-year minimum contract last week, but the knee injury caused Dallas to pull out of the deal.
Lewis scored 4.5 points per game last season for the Miami Heat.
It is the second consecutive offseason the Mavericks have discovered an injury during a physical after agreeing to terms with a player. Last season, Devin Harris needed toe surgery and agreed to a reduced contract before re-signing this summer.
- Paul Palladino