Oliver Kahn remains wary of the effect Pep Guardiola could have on Bayern Munich's style of play and subsequent results, when the Spaniard signs for the Bundesliga leaders in the summer.
Rising to prominence for his focus on youth team players in addition to his introduction of a devastatingly effective brand of possession football, Guardiola became one of the hottest coaching names available after he stepped down from his Barcelona post last summer.
Although die Roten won the race to hire the sought-after 42-year-old, Kahn has moved to quell the hype around the appointment, stating it may well prove to be far from a bed of roses.
"Guardiola brought up players from youth to professional levels, but Bayern's players need not possess the same level of automatism as Barcelona's do," wrote the former Germany international in his column for Bild.
"To internalise his systems will not happen in one day. Unlike [ex-Bavarian coach] Louis van Gaal's single-minded usage of the ball to achieve an end result, Guardiola's system is more flexible, with possession central to play.
"Anyone not willing to participate in this collective movement will find it very hard in his system. For example, part of his success lay with Lionel Messi's use as a 'false number nine', but it is interesting to see if Bayern can play in the future like that.
"Guardiola and sports director Matthias Sammer must develop and implement a consistent philosophy. Doing so will be a decisive factor in the battle to be Europe's number one team."