Jose Mourinho and Pep Guardiola have rotation questions to answer ahead of Real Madrid's and Barcelona's Saturday games

With crucial games having already been and also on the way, both of the Spanish giants look to make full use of their squads in this weekend's league fixtures
For all the talk of there being no mathematical certainty, and no complacency, and no giving up, it's fairly clear that La Liga is over. The champions' eight-point advantage is almost certain not to be overtaken now, meaning that both Barcelona-Osasuna and Valencia-Real Madrid are largely without meaning for the top two sides involved.

Thus for each coach the questions are more about selection and rotation. With injuries, suspensions, and tactical worries to deal with, it's clear that there's much to think about.

Capital Concerns

Jose Mourinho does not have his sorrows to seek ahead of the Mestalla meeting. Sami Khedira is out for sure and will miss the first leg of the Champions League at the very least, necessitating a midfield reshuffle. The return of Lassana Diarra perhaps doesn't fully compensate for the German's absence.

Assuming four at the back, we could see a wholly unusual defensive line. Juanfran may earn a start due to the absence of both Sergio Ramos and Alvaro Arbeloa, while there are rumblings that both Ricardo Carvalho and Pepe could be rested, or at least the latter moved forward to midfield, as against Athletic Bilbao. It is a risky gambit for a coach to take: winning at Athletic 3-0 is one thing, but doing it against Valencia is quite another, and this team's new-found confidence could be shaken if the new-look defence fails to gel at the Mestalla.

Further forward the questions are even more important. Real Madrid saw success midweek with Cristiano Ronaldo alone in the middle up front, supported by two wide players, and with Pepe and Xabi Alonso juggling their duties alongside Sami Khedira. Simple it was not, and it couldn't have developed overnight. Valencia play a different game and Mourinho, as a schemer of a coach, must surely adjust his formation. But again, there is a risk factor: the travails of pressing Barcelona out of the game for another 90 minutes await, and the more practice, the better.

WILL THEY OR WON'T THEY? | Mourinho's selection dilemmas
Lassana Diarra
Gonzalo Higuain
Esteban Granero
Ezequiel Garay

Defensively able and full of energy - but he offers less going forward than Pepe did on Wednesday

Ready for his comeback, but would prefer a 4-4-2, and thus a change of shape for the rest

Could form a new-look midfield with Lassana Diarra. But would this would necessitate upheaval elsewhere?

No chance of starting midweek, but could he take the strain off Carvalho ahead of the Champions League?

What's more, the Portuguese boss' hand is forced by the players available. With Khedira out there was always going to be some measure of change, and it may be in this instance that Lass Diarra and Esteban Granero audition for potential roles midweek.

The question then is what the former can offer in comparison to Pepe, who will almost certainly retain his defensive midfield spot at the Bernabeu. They seem on the surface to be very much alike, with the former Porto man offering slightly more by way of positional ability in the opposing half. As a replacement for Khedira, Lass does not quite suit... but does Granero? Perhaps the simplest thing to do is for Mourinho to play a more conventional, four-man midfield.

Finally, it seems as though both Ozil and Di Maria have earned their spots further forward for the Champions League, but whether or not the German plays on Saturday is anyone's guess, given his clear exhaustion after his heroics midweek. The Argentine is out injured, of course, and it could be a rare chance for his countryman Gonzalo Higuain to enter the side up front as part of a twosome. Again, the only danger here is that Ronaldo may be placed out wide, where he most likely will not be on Wednesday.

Pep's Permutations

Guardiola has far fewer enforced changes to make. Carles Puyol, who sat out Wednesday's cup loss entirely, is training normally, with just Eric Abidal, Adriano, and Bojan out of the squad.

At the back it's likely to be Dani Alves and Maxwell on the flanks, with the latter looking to gain some minutes and the former seeking to regain the form that deserted him midweek. In the middle Gerard Pique will surely offer some much-needed constancy, but then the questions begin. Will Sergio Busquets be given another chance to practice in this position? Will Javier Mascherano? What of youngster Andreu Fontas?

Further forward, Guardiola won't change his style - that much is already clear. The aim will be to hold the ball, attack, and score goals, either at home to Osasuna or away to Real Madrid. How that's achieved is another matter entirely.

Up front, Guardiola is only missing Bojan, who would be unlikely to cause much of a selection headache in any case. Yet there are so many options available to him that the regular three of Pedro, Messi, Villa may be open to change. Ibrahim Afellay would surely seize a chance to impress against lower opposition, or perhaps Andres Iniesta's ability to cut back for the ball then make a diagonal pass from deep would be ideal preparation for Wednesday.

WILL THEY OR WON'T THEY? | Guardiola's tough choices
Ibrahim Afellay
David Villa
Lionel Messi

Has looked far from confident in recent weeks but could give Pedro - or, in another system, Messi - a break

The youngster's earned a chance at first team action, that much is clear - but at whose expense?

Could a game on the bench help him? Or how about changing the system to put him in the middle?

If Villa does move to the '9' slot, Messi will probably play wide instead of deep in the centre. Or a rest?

The biggest question of all could surround both David Villa and Lionel Messi. Has the latter, at long last, earned a rest? Far from being coddled as the game-changing star that he is, Pep tends to use Messi whenever and wherever possible. Right now he's playing in the middle, of course - and David Villa isn't. The striker, goalless in eleven matches, may relish the chance to return to a central position, so a direct switch with Messi isn't entirely out of the question.

Further back, Thiago is knocking on the door of the first team. Sergio Busquets, the metronome for Barcelona possession play, could potentially be sacrificed entirely for this game in order to give him a break, but the youngster then has some very important boots to fill.

Neither of these coaches is likely to give too much away ahead of Wednesday, with Mourinho apt to spring a surprise when even his closest competitors least expect it. Thus the most fascinating aspect of Saturday's games may simply be as basic as which individuals play well and which do not. The world, as always, will be watching.

Follow Ewan Macdonald on Twitter: @ewanmacd

Follow on . Get the latest football news direct... Check out's  page; be part of the best football fan community in the world!