Cornal Hendricks will not make his comeback for Toulon after the South African wing left the Top 14 club without playing a game.
Hendricks, capped 12 times by the Springboks, was forced to stop playing last year after being diagnosed with a heart condition.
The 28-year-old said he was confident of resuming his rugby union career after getting a second opinion from independent sports health experts.
Three-time European champions Toulon last month announced they had signed Hendricks on a short-term deal after Drew Mitchell sustained an injury.
However, the French club on Friday said Hendricks will not ply his trade at Stade Mayol following extensive medical tests over a three-week period.