The left-back missed the Spanish champions' pre-season tour of the USA because of his obligations with Brazil's Under-23 team in London, but is back in his club side's reckoning
The 24-year-old missed the first few weeks of the Blancos's pre-season due to his obligations with the Selecao, but is now available again, having touched down in the Spanish capital.
Marcelo's Brazil were beaten 2-1 by Mexico in the final of the Olympics on Saturday.
Madrid resumed regular training action on Wednesday after three days of rest following their pre-season tour of the USA, where they played friendlies against Celtic, AC Milan, Santos Laguna and LA Galaxy.
Coach Jose Mourinho is currently preparing his squad for Sunday's Liga opener against Valencia. The match at the Santiago Bernabeu is scheduled to kick off at 19:00UTC.