After a season in which injuries and position changes cast doubts onto Javi Martínez’s role with Bayern Munich, the 25-year-old seemed poised to be a central figure in Pep Guardiola’s new defensive system. But the work that Martínez has done in the preseason has now been erased, with the midfielder suffering a career-altering ACL tear in Borussia Dortmund’s 2-0 defeat of Bayern Munich in the DFL-Supercup.

The injury is a very expensive one for Bayern — not just monetarily (Martínez remains the club’s most expensive transfer following his move from Athletic Bilbao), but also positionally. The club have announced that the Spaniard will miss the rest of 2014, and there is a chance that he could be out well into the spring.

Javi Martinez hurt

This diagnosis comes just five days after Bayern lost Rafinha, whose career resurgence pushed Philipp Lahm to midfield, to a ligament tear in his ankle. That leaves the German champions with six defenders on professional contracts, creating the first major depth dilemma since their return to German and European dominance two years ago.

With Bayern Munich’s shellacking from Real Madrid fresh in his mind, Guardiola dedicated a good portion of the preseason to developing a new defensive scheme featuring a back three. Martínez was one of the major parts of that system coming to fruition, getting time as both a sweeper and one of the outside center backs. His loss now leaves a major vacuum in the spine of the team that Guardiola will have to go back to the drawing board to compensate for.

During preseason preparation, Bayern have been suffering from a lack of personnel due to the deep World Cup runs of Germany and Brazil. Their two starting defenders, Jerome Boateng and Dante, spent most of Bayern’s preseason on holiday, which meant Guardiola had to test out David Alaba, Rafinha, Holger Badstuber and Martínez — with the former two of those players being traditional attacking fullbacks — in a three-man defense. Between recent injuries and the return of those players, Bayern could be forced to return to a four-man defense.

But the loss of Martinez isn’t just a problem at the back. His absence represents an even larger personnel problem in midfield. Even though Sebastian Rode — a fairly defensive midfielder — has replaced dynamic attacking midfielder Toni Kroos, Martínez remained the best shield in defense in front of the Boateng-Dante blockade. His absence could shackle Bastian Schweinsteiger deeper in midfield, something that would continue to stall their attacking ambitions.

Last season, Lahm patched over a lot of midfield depth issues after Guardiola repurposed the world-class fullback into a holding player. Lahm may need to return to right back with the injury to Rafinha, although 19-year-old Pierre-Emile Højbjerg has roamed the right flank as a more attacking wingback for most of the preseason.

Fortunately for Bayern, the summer transfer window will be open long enough for them to scout and possibly transfer for a replacement, whether an interim one or a permanent solution. The club was linked with AS Roma’s Mehdi Benatia earlier in the summer, but that will cost Bayern close to €40 million. Beyond Boateng and Dante, Bayern’s only center-back possibility is Badstuber, who has missed the last season and a half with knee troubles himself.

Guardiola’s solutions are never simple, and he will try to orchestrate a score that will continue to be an attractive spectacle. With Bayern opening their domestic season next weekend, he does not have a lot of time to do so.