Alvaro Arbeloa has been declared unfit to face Barcelona in the first leg of the Copa del Rey clasico tonight. Ever since Sergio Ramos has moved to, and excelled in, central defense, the Madrid squad has been atypically thin in a crucial position this season. With the world's most feared attacking unit up next, what options can Mourinho come up with?

1) Lassana Diarra playing at the right seems to be the most popular choice with most pundits and fellow Madridistas. The fact of the matter is, he does have previous experience playing there, as it was his usual position during his (undistinguished) stints with Arsenal and Chelsea in his youth, and he has been tried out over there by Mou occasionally this season. Theoretically, a decently pacy defensive midfielder like Lass should make for a solid fullback. But the surprising thing to be noted in his performances there this season has been the fact that he has given a decent account of himself going forward, but has been leaving gaps behind (that he is simply not fast enough to compensate for, a la Sergio Ramos). Would it really be a good idea to put up a glaring weakness like that against either/both Alexis and Pedro? They're both hardworking and lightning quick wingers, and they'll keep switching positions and harrying the defender they're up against.

2) Fabio Coentrao- he filled in at RB in the last clasico, to frankly underwhelming results. Coentrao still doesn't  look like a 25 odd million Euro player to this author, but one attribute that is undeniably remarkable about him is his work rate. Couple that with a team ethic that shows an apparent readiness to play in any position his manager asks him to, and you have a solid, committed player in your hands, essential to fill in the gaps in any high quality squad. But he is almost exclusively left footed, and appeared painfully tentative going forward, or even tackling with any conviction in the 3-1 clasico defeat earlier this season. A similar performance this time will lead to the absolute nullification of a threat from an important attacking outlet for a team of Madrid's ilk.

3) Shifting Sergio Ramos to fullback again would perhaps be the least desirable to Mourinho, going by his team selections this season. Ramos has been excellent, even imperious at times in the center, lending a level of solidity to the defense that no one could've foreseen from a RB with a history of galloping forward into opposition territory. Bringing him back to his original position would mean that Pepe would have to be used in defense, and not as a DM. Even more pertinently, choosing Pepe's partner would be an unenviable task - Albiol is far, far too mediocre to cope up with Barca's attackers, and Varane is too inexperienced to be thrown to the lions.

This conundrum would certainly not be as much of an issue against usual teams. All 3 players stated above bring in their own qualities - be it solidity or adventure, and they would be invaluable depending on whether the opponent suited their styles. However, Barca brings patient, cerebral attacks to the mix, and an ability to both sneak past opposition defenses, or scorch the earth before them.

From the viewpoint of the manager and the supporting public in general, Lass Diarra is the most likely option of the 3, but I'd certainly have my reservations.

So what do you guys think?

Hungry for more?! Then see Muna and @footballstrat's written answers to the topics we discussed in the pre-Clásico podcast,  Aaron's Hot or Not, Karan's Here we are again and tactics, Ankit's This is not another game, and Apakshit's preview.