<span class="fcc003318px">Demichelis ruled out, Ribery very doubtful</span></p> Enforced line-up changes will be the order of the day for Bayern when they travel to Belgrade to face FK Crvena Zvezda in the UEFA Cup on Thursday. Martin Demichelis is definitely out of the clash in the Serbian capital with a severe bout of flu, while midfield star Franck Ribery is rated extremely doubtful for the fixture. Speaking after Tuesday training at the Säbener Straße, Ottmar Hitzfeld estimated the France star’s chances of playing at “no more than 30 percent”. Ribery has complained of a stiff hamstring since Saturday’s trip to Bochum and was again unable to train on Tuesday. A final decision on the player’s fitness will be taken on Wednesday morning before the squad’s scheduled departure for Belgrade. Bastian Schweinsteiger is standing by in the event of Ribery failing to recover. Van Buyten likely to partner Lucio On a more positive note, Demichelis' fellow centre-half Lucio resumed the squad programme on Tuesday and is available to play at the Marakana stadium in Belgrade, where he will almost certainly be partnered by Daniel van Buyten. “He’s coming with us,” confirmed Hitzfeld, indicating he would omit Valerien Ismael from the matchday squad. Rookie pro Mats Hummels will be the reserve centre-back, with youthful talent Toni Kroos providing midfield cover. Van Buyten, troubled by a bruised thigh since appearing for Belgium last week, is by no means a certain starter on Thursday, prompting Hitzfeld to try out a makeshift back four comprising Philipp Lahm, Lucio, Christian Lell and Marcell Jansen in Tuesday’s practice match. Valuable experience for Rensing Oliver Kahn understudy Michael Rensing is set for a fifth match in a row between the sticks. “Getting a decent run in the side has been great for me. I’m looking forward to playing the next two or three games as well,” the 23-year-old told Tuesday’s daily news conference. “It’s been a valuable experience, and very useful to slot into the rhythm of playing at the weekend, in midweek, and then again at the weekend,” Rensing explained. “It’s important for me to appreciate how it works, especially looking ahead to next season.“ After many years shadowing Kahn, Rensing will be promoted to number one keeper at the club when the captain ends his active career in summer 2008. Back to the roots for Rensing The match in Belgrade has special personal significance for Rensing. His mother hails from the former Yugoslavia, “and in the 1990s I used to follow all Red Star’s matches.“ A number of Rensing’s relatives who live near Belgrade will be watching from the stands on Thursday. “It’s very nice indeed,” the player commented. It also means a handful of Serbian spectators will be cheering for Rensing and his team-mates when they run out at the Marakana, but the former Germany U-21 keeper is expecting an overwhelmingly hostile reception. “It’ll be boiling with emotion,” Rensing predicted, “but it’s important to start with three points. It would allow us to approach the remaining games calmly and confidently.“</p> <span class="fcc003318px"></span></p>