The 23-year-old defender missed the Blancos' 4-1 Liga win over Atletico Madrid on Wednesday due to injury, and there were doubts about his availability for Saturday's match at the Santiago Bernabeu.
Nevertheless, Marcelo returned to the training ground again on Friday, and is expected to make the match squad for the game against Sporting.
The return of the left-back means that Fabio Coentrao is likely to lose his starting berth again after replacing the Brazil international versus Atletico.
Saturday's match in the Spanish capital kicks off at 20.00CET.
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