Chelsea boss Maurizio Sarri has claimed his side are in ‘trouble’ as they face a defensive crisis ahead of their Europa League semi-final clash against Eintracht Frankfurt.

The Blues coach only has two fit centre-backs to choose from, with David Luiz and Andreas Christensen set to start in Germany.

Germany international Antonio Rudiger has been ruled out for the rest of the season, while Gary Cahill was not named in the 19-man travelling squad. Cahill has been struggling with an Achilles tendon issue and Sarri says he is worried about his team’s chances.

Chelsea have conceded in each of their last four matches and Sarri may need to use Cesar Azpilicute in the middle if he loses another man to injury. He told reporters: “Cahill is out, a problem with the Achilles tendon. He is out for the moment.

I hope to have him back in one week. But he is out, starting four or five days ago. So we are in trouble with the centre-backs. “In training we played with (Cesar) Azpilicueta at centre-back, in case as he is the only one who can play there.

“It is normal, it can happen that we are in trouble. We have had a lot of games and been lucky with injuries. Worried? A little.”

Despite their home advantage, Frankfurt are the slight outsiders at odds of 2.88. The draw is 3.25, while Chelsea are 2.50 to grab an away win.

After their Europa League exploits, Chelsea take on Watford but Sarri is set to name a strong team in both games as he looks to win his first trophy and qualify for the Champions League.