Real Madrid could be without left back Marcelo and Croatia midfielder Luka Modric for their Champions League last-16 second leg at Paris St Germain in two weeks' time after the pair were diagnosed with hamstring injuries.
Marcelo was one of Real's best performers in the 3-1 win at the Santiago Bernabeu last week and scored the final goal of the game to give them a two-goal cushion in the tie.
He was forced off, however, during his side's 5-3 win at Real Betis on Sunday with a hamstring injury.
Real released a statement on Tuesday confirming the player had injured his right hamstring and said Modric, who played against PSG but was an unused substitute against Betis, had the same injury.
As is customary at Real, the club did not reveal how long either player would be out of action although Spanish newspaper Marca said there was a possibility both players could return in time for the second leg at the Parc des Princes on March 6.
Real coach Zidane told a news conference ahead of his side's Liga game against Leganes on Wednesday that he was optimistic about Modric.
"He has sustained a hamstring problem which is why he didn't train and he is focusing on recovering as quickly as possible," Zidane said.
"I think it's a small problem and as always I have every faith in everyone that works here, the doctors and physios, that they will ensure he returns quickly."
Modric and Marcelo have been ruled out of Wednesday's game away to Leganes along with German midfielder Toni Kroos, who is nursing a knee injury sustained after the first leg against PSG.
Real are fourth in the Liga standings on 45 points, 17 behind leaders Barcelona, but victory over Leganes would lift them above Valencia and into third place.
Leganes, who are 13th, are in their second season in Spain's top flight and knocked Real out of the King's Cup in the quarter-finals last month, before eventually losing to Sevilla in the semis.