PSG and France forward Kylian Mbappe (AFP)
Kylian Mbappe is doubtful for PSG because of a left-foot injury, while Madrid is likely to be without Toni Kroos because of a muscle problem.
Madrid, which lost the first leg 1-0 thanks to Mbappe's stoppage-time winner in Paris, is certain to be without Casemiro because of a suspension and may not also count on a fully fit Federico Valverde after a bout with the flu.
Setting up the midfield will be no easy task for Ancelotti, as Casemiro plays a key role in keeping the Spanish team balanced. The absence of Kroos would hurt the team more offensively than defensively, as the German veteran helps the team transition into attack. Kroos returned to training but a decision on whether he will play likely won't be made until Wednesday.
Young Frenchman Eduardo Camavinga will likely go into the midfield alongside Luka Modric and possibly Valverde, who missed the Liga game against Real Sociedad last weekend. The 19-year-old Camavinga played well in that match, scoring a superb opening goal in the 4-1 victory that increased Madrid's lead in the league. He had Casemiro by his side, though, which will not be the case against PSG.
Madrid's midfield issues will likely make it easier for Lionel Messi, who gets another good chance to finally come through with a big performance for PSG and live up to his status after joining from Barcelona. He will take over most of the spotlight if Mbappe can't play after getting hurt in Monday's training session.
Initial medical exams showed the injury wasn't serious, but PSG said he was undergoing treatment and his fitness would be reassessed closer to the match.
Mbappe, who has been linked with a move to Madrid when his contract expires at the end of the season, has been in stellar form with 24 goals and 17 assists in all competitions.
He was suspended at the weekend when PSG lost at Nice 1-0 in the French league. Pochettino used former Madrid forward Angel Di Maria along with Neymar in attack, and Di Maria is likely to play again if Mbappe can't make it. The Argentine played under Ancelotti in the coach's first stint with Madrid.
Pochettino is set to be without former Madrid defender Sergio Ramos and Spaniard Ander Herrera because of injuries, and Achraf Hakimi, another former Madrid player, was listed as doubtful. Ramos will make the trip to the Spanish capital despite not being available.
Ancelotti can't count on suspended left back Ferland Mendy, with veteran Marcelo likely taking over for him.
Madrid eliminated PSG at this stage in 2018 en route to winning the title for the third year in a row, although the French club came out on top in the two previous knockout encounters between the teams.
Madrid is the record 13-time European champion, while PSG is seeking its first Champions League trophy.
A crowd of 60,000 _ the biggest since the coronavirus pandemic started _ is expected at Santiago Bernabeu Stadium, which remains below its full capacity because of renovation work.
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