Schalke v Chelsea: Knobbly knees and wobbly form, but the Königsblauen pose a real threat to Blues' qualification hopes Borussia Dortmund goalkeeper Roman Weidenfeller assured everyone this week that his side are "back in Champions League mode." But then, faced with Arsenal and in need of three points, Jürgen Klopp's side were never going to be anything but. What is less certain is if their old rivals Schalke 04 will follow suit. For Schalke's Champions League mode is distinctly different to their normal mode. In 2011, they found themselves simultaneously flirting with the relegation zone and battling Manchester United - albeit in vain - for a place in the Champions League Final. This time last year they were riding high in both competitions before plummeting dramatically in the league. And now they find themselves with a spotless start to their European campaign and an everything but spotless record in the league. Schalke are an anomaly. Gone are the days when they would miss out on their long awaited first Bundesliga title by a matter of seconds. Instead, the Königsblauen float tentatively around the top of the German game, rarely too far in points alone from the real elite, but always so distant in actual quality. So it is this year, with their current Bundesliga standing in a definitively flattering fifth place. Victories against Mainz and most recently Eintracht Braunschweig have been scraped in ungainly fashion, while pitted against FC Bayern they were torn to shreds in a manner which several lesser teams have avoided. Had it not been for the surprise arrival of Kevin Prince Boateng in late summer, their predicament may well have been a lot less comfortable by now. It has always been so for Schalke in recent years. One outstanding player has boosted not only the technical abilities of the team, but also their fragile psychology. Raúl served this purpose in his two years at the club, while more recently it has been the likes of Lewis Holtby and - more notably - Klaas Jan Huntelaar. Now it falls to Boateng, who will line up in the Veltins Arena tonight knowing that his return from a knee injury is nothing if not premature. The Berlin born Ghanaian international will return after seventeen days of next to no football with the weight of Gelsenkirchen's expectation on his shoulders. He is, bizarrely, one of three key Schalke players to have had trouble with his knees in recent weeks. Huntelaar remains sidelined until Christmas, while defensive midfielder Marco Höger was carried off with a heavily bandaged joint during the Braunschweig game on Saturday. Knobbly knees and wobbly form, then, perhaps do not give Schalke much cause for optimism. But, you never quite can tell with Schalke - particularly when it comes to Europe. As John Terry so eloquently voiced at the pre-match press conference, (he's seen video clips and everything), Chelsea expect a tough game. The fulfilment of that expectation depends on two things, however. Firstly, as Schalke's young talent Leon Goretzka put it "it's quite clear that we need to put in a better performance than we did against Braunschweig." Secondly, Boateng's knee must hold. Even with their injury woes, Schalke's potential is not in question. The likes of Benedikt Höwedes, Julian Draxler and Adam Szalai are, at their best, more than capable of getting a result against Chelsea at home. It is psychologically where they may yet fall. Incapable of converting positive results into genuine form, Schalke need a figure like Boateng to maintain some sort of confidence in their own ability. In a team full of young players with a capable but hardly inspiring manager, Boateng can be the spark Schalke so often miss. Without him, they can be far more easily brought to their knees.