Messi can look to top-ranked tennis player Rafael Nadal as another elite athlete who was reserved when not playing, spoke mostly Spanish and had trouble attracting deals outside of Nike and several regional agreements.
He matured into an athlete with movie-star looks, brandishing baseball bats and tennis rackets with the same intensity as his later heroes would wield swords.
"The implementation of the athlete biological passport is an important step in the evolution of the tennis anti-doping program as it provides us with a great tool in the fight against doping in our sport, " said ITF President Francesco Ricci Bitti.