Marcelo pulled up after feeling a sharp pinch to his right hamstring in the Betis-Real Madrid game and will undergo a series of tests on Tuesday to determine the extent of the injury. Judging by the player's expression, it looks likely that he has suffered a muscle tear - we'll find out tomorrow what grade of injury Marcelo has and long he faces on the sides; but with the Champions League return leg against PSG just 15 days away, it looks unlikely that he will be back in time for the decider in Paris. For that reason, Zidane is already weighing up who could come in as a substitute at left-back. He has three possible options - two viable ones and one which involves more risks but .
1. Nacho: the most plausible option
Out of all of the alternatives, Nacho is the top choice to fill in for Madrid on the left in Paris. After taking a 3-1 lead in the first leg, Zidane's team must defend their advantage, and if they score once, PSG will need to score three to take the tie to extra-time. That calls for a solid strategy at the back to contain Mbappé-Cavani-Neymar and Nacho provides the kind of security the team will certainly need in the French capital. He did a great job covering for the suspended Dani Carvajal at right-back in the first leg and although he did suffer at certain moments, he managed to keep Neymar at bay for much of the game - especially after the Brazilian was booked for kicking him early on.
Carvajal will be back in Paris and it is looking highly probable that if Marcelo doesn't make it in time, Nacho will be fielded on the left and Carvajal on the opposite flank. Nacho has been used regularly this season and has clocked 2,500 minutes of playing time - only less than Casemiro and Cristiano.
2. Theo: still yet to convince...
While Nacho is the number one choice to stand in for Marcelo against PSG, the natural substitute is Theo Hernández. The French full-back, who joined from Atlético de Madrid last summer for 30 million euros, hasn't quite lived up to expectations following the superb season he had on loan at Alavés in 2016-17. He has only clocked 1,043 minutes on-field this season and has looked a shadow of the player who shone at Mendizorroza. He's set up a couple of goals but that's pretty much been the only highlights of his season so far.
He's looked unsure going forward and insecure at the back, as was evident at the Benito Villamarín; Sergio León got in behind him in the move that led to Betis' third goal and he was out of position at other moments in the game when Madrid could have been but weren't punished. He might be able to deliver in LaLiga, but in the late stages of the Champions League against the likes of Mbappé and with the experienced Dani Alves on that wing, it could be a lit too much to ask of a 20-year-old who is only in his second season as a professional and who hasn't convinced when he has played.
3. Three centre-backs: a big risk to take
The third possibility open to Zidane would be to field three central defenders - Ramos, Varane and Nacho, flanked by Carvajal on the right and another player on the left, among the options in such a set-up are Theo, Achraf, Asensio (who played in the role against Celta last season)... or even Gareth Bale... Bale started out as a left-back and played in the position with Southampton and in his early days at Tottenham; dropping him there would allow Zidane to make the most of the good moment of form his other forward players are in (Cristiano, Asensio, Lucas Vázquez, Isco...), and Bale's pace would give Madrid some security from PSG's counter-attacks. The only downside is that Bale has not played there for years and it's a risk which could just as easily backfire as work out. On the few occasions when Zidane has gone 3-5-2, results have been less than convincing...