The Real Madrid midfielder is facing an anxious wait on news of the knee injury he suffered during the international friendly with Italy on Friday night.
The 26-year-old has torn the anterior cruciate ligament in his right knee, reports Sky Sports News, but hopes remain he could be fit in time for the finals in Brazil, according to Germany head coach Joachim Low:
This is a bitter blow for Sami and all of us.
He is a great player on and off the pitch, he is always thinking positively and this will help and I am optimistic that he will be back in time for the kick-off of the World Cup.
We wish him all the best and keep our fingers crossed that the surgery goes well and he can quickly get into rehab.
Khedira lashed out at his treatment by the Spanish media last month in the wake of the departures of Jose Mourinho and Mesut Ozil from the Bernabeu, as Ben Burrows of the Daily Mirror noted, but his presence in the Real team remains an important one for Ancelotti.
Khedira has provided a crucial presence in the Real team this season, offering a battling midfielder with an eye on retrieving the ball in front of the defence.
His passing this season has also offered a 91 per cent success rate, according to statistics provided by Squawka.
His role might not have the glamour element of his team-mates, but Khedira represents a backbone for Real in his sweeper role.
That element has not gone unnoticed elsewhere and Khedira has been the subject of transfer speculation in recent weeks, with a move to the Premier League particularly gaining attention.
The future of Ramires at Stamford Bridge is the key to Khedira's future, according to James Dickenson of the Daily Express, who claims the Chelsea man is wanted by Ancelotti in the January transfer window.
Real currently trail La Liga leaders Barcelona by six points, and Ancelotti will now have to consider his options, but the loss of Khedira will leave a gaping hole at the Bernabeu this season.