Douglas Costa must deliver straight away

While 30 million euros might not be a lot in the context of modern football transfers or Bayern Munich's bank balance, it does seem an awful lot for a player who remains fairly unproven. My fingers were burned when Henrikh Mkhitaryan's transfer to Borussia Dortmund didn't turn out as planned - and he nearly cost just as much - so when I read Bayern were close to signing Douglas Costa, I couldn't help but wince.

Costa has been hailed as a replacement for Franck Ribery, whose ankles are made of the same stuff as Bastian Schweinsteiger's legs, and at just 24-years-old that seems reasonable. Of course in the club's first press conference of the new season, sporting director Matthias Sammer said Costa wasn't a replacement for Ribery. With his versatility on both flanks and Pep Guardiola favoring a fluid front four, Costa will almost certainly feature on the right at some point in the new season.

Most Bayern fans remember Costa as the man who continuously chipped away at their players during Shakhtar's 7-0 Champions League drubbing last season. Although the injury that Ribery incurred in the game against Shakhtar wasn't Costa's fault, Bayern fans won't have particularly fond memories of the Brazilian who kicked his way around the park the last time they saw him.

There are all sorts of complimentary reports from the Brazilian press about Costa's quality and even as far back as 2008, a whole host of European clubs - Bayern included - were apparently interested in bringing the Brazilian to Europe. But in the end he went to Shakhtar Donetsk. While Shakhtar have come a long way and are regulars in the Champions League, that move says a lot about the youngster's potential.

So at 24, it's about quality and whether he has enough of it. Nine international caps suggests yes, but perhaps only fleeting amounts. Alongside the increased weight of expectation that accompanies from joining Bayern and the hefty fee, the winger is also following in the footsteps of the legendary Giovane Elber, who was rather successful at Bayern. Granted he will need some bedding-in time, but it cannot be long. Then again, regardless of whether newly signed 24-year-old's really are worth 30 million euros or not, Bayern will still win the league.