Jupp Heynckes has allayed fears Jerome Boateng's World Cup participation is in doubt after he suffered a season-ending thigh injury, adamant he will "definitely" be involved in Germany's title defence. Boateng was forced off after just 34 minutes of Bayern Munich's Champions League semi-final first leg defeat to Real Madrid on Wednesday, with the centre-back reportedly in danger of being out for up to six weeks. As a result, it had been suggested he was a major doubt for the World Cup, with Boateng saying on Thursday he is ready to "fight" to be fit for Russia, ahead of Germany's first game taking place against Mexico on June 17. But Heynckes is certain Boateng will be fit and ready for training well before Germany's opener and he had some stern words for those who predicted he would be sidelined for the showpiece. "Jerome I spoke to just now," said Heynckes. "He is walking normally. I don't know why you guys said he won't be able to play in the World Cup. "You all seem to be physicians. There's no problem [with playing at the World Cup] whatsoever. He will definitely be part of the World Cup and will even be able to train beforehand. "With [Arjen] Robben we'll see. He's doing okay, but I'm not quite sure if it's a muscle, nerve, or back problem. Some team news from #Heynckes : " @Javi8martinez will be back training tomorrow, but we'll have to wait and see with @ArjenRobben . Neither will be on board tomorrow." #FCBSGE pic.twitter.com/rr2tFZAqWe — FC Bayern English (@FCBayernEN) April 27, 2018 "It's difficult to find the right diagnosis right now, so we'll see. With David Alaba I had to decide if I wanted to let him play tomorrow [Saturday]. "He trained today without problems, but in the last few days he's trained very differently and didn't train completely. He won't play tomorrow." Saturday's Bundesliga clash with Eintracht Frankfurt sees future Bayern coach Niko Kovac make his first appearance at the Allianz Arena since being confirmed as Heynckes' successor. The two sides will do it all again three weeks later in the DFB-Pokal final and Heynckes urged the gathered media to go easy on the Croatian once he is in charge at Bayern. "I think the situation, the fact we play Frankfurt in the cup final [so soon after playing in the league], it's unusual," said Heynckes. "To play them now, three games before the end and then play again in the cup final, it's unusual, but I'm not worried about meeting Niko. "He's a young coach who wants to take the next step in his career. I hope he will do a good job, I hope you [the reporters] support him and that you aren't so critical. "I hope you give him a little time to settle in, but the way I know you, you're so charming towards the manager, it's mindboggling."