MADRID, April 30 -- Real Madrid could be without three key players as they look to book their third consecutive appearance in the Champions League final on Tuesday night.

Madrid defend the 2-1 lead they claimed in Bayern's Allianz Arena last week in front of their supporters in the Santiago Bernabeu, but they will have to do so without right back Dani Carvajal and possibly midfielder Isco.

Isco damaged his shoulder in Munich after falling badly and although he trained on Sunday he is a doubt, while Carvajal has a muscle injury which will sideline him for two to three weeks, giving Madrid coach Zinedine Zidane a selection headache.

If Nacho Fernandez is fit, he will be able to cover at right back, but the central defender, who has been out for almost a month only trained with the first team for the first time in a month on Sunday and is also doubtful for Tuesday.

Achraf would be the natural replacement, but he lacks experience for a European semi-final means Zidane will probably not risk him and Lucas Vazquez may be tasked with dropping deeper to defend, even though he will have to curb his attacking instincts.

Meanwhile Mateo Kovacic could replace Isco, meaning Gareth Bale will once again start the game on the subs' bench.

Nobody at Madrid will have forgotten last year's quarter-finals where they defended a 2-1 lead against Bayern and saw how the German side took them into extra-time before finally falling 4-2 after a series of controversial decisions.

This year's quarter-final return leg against Juventus should also serve as a warning that Madrid can't relax as they saw a 3-0 first leg lead wiped out by the Italians with only an injury time penalty from Ronaldo saving them from extra time.

Bayern also have players out injured with Arturo Vidal, Arjen Robben and Jerome Boateng all sidelined as they look to prevent Madrid reaching their third Champions League final in 3 years.

MADRID, April 30 -- Real Madrid could be without three key players as they look to book their third consecutive appearance in the Champions League final on Tuesday night.

Madrid defend the 2-1 lead they claimed in Bayern's Allianz Arena last week in front of their supporters in the Santiago Bernabeu, but they will have to do so without right back Dani Carvajal and possibly midfielder Isco.

Isco damaged his shoulder in Munich after falling badly and although he trained on Sunday he is a doubt, while Carvajal has a muscle injury which will sideline him for two to three weeks, giving Madrid coach Zinedine Zidane a selection headache.

If Nacho Fernandez is fit, he will be able to cover at right back, but the central defender, who has been out for almost a month only trained with the first team for the first time in a month on Sunday and is also doubtful for Tuesday.

Achraf would be the natural replacement, but he lacks experience for a European semi-final means Zidane will probably not risk him and Lucas Vazquez may be tasked with dropping deeper to defend, even though he will have to curb his attacking instincts.

Meanwhile Mateo Kovacic could replace Isco, meaning Gareth Bale will once again start the game on the subs' bench.

Nobody at Madrid will have forgotten last year's quarter-finals where they defended a 2-1 lead against Bayern and saw how the German side took them into extra-time before finally falling 4-2 after a series of controversial decisions.

This year's quarter-final return leg against Juventus should also serve as a warning that Madrid can't relax as they saw a 3-0 first leg lead wiped out by the Italians with only an injury time penalty from Ronaldo saving them from extra time.

Bayern also have players out injured with Arturo Vidal, Arjen Robben and Jerome Boateng all sidelined as they look to prevent Madrid reaching their third Champions League final in 3 years.