It won't be easy for Real Madrid to shake up its rustiness after 15 days of International duty. Furthermore, Mourinho's players will need to do it without the three pure fullbacks of the roster. And, of course, Real Madrid can't afford to lose any more points.
Jose Mourinho will need to make a tough decision before the game. Sergio Ramos appears to be confirmed as the team's new right back, but whether or not Mourinho plays Nacho Fernández on the left is still unknown. The Academy defender doesn't play at that position with Castilla, but Mourinho has tested him both right and left in these past preseason stages. He's Castilla's most mature player, and given that Celta shouldn't be a big threat, it seems reasonable to start him. it might be a different thing against Borussia Dortmund, though.
This should also mean a chance for Raúl Albiol. Varane came back to the Spanish capital slightly injured after playing with France's U21, but he has recovered and could feature in Mourinho's starting XI. But Albiol did only play 20 minutes with Spain, so he should be Mourinho's choice.
Midfielder Michael Essien worked under Mourinho these past two weeks while his teammates were in duty, so he could also start in Khedira's spot. Modric is also getting into rhythm, but Mourinho might not want to start the Croatian playmaker besides Xabi Alonso yet.
Things are much clearer upfront. Özil, Di María, Cristiano Ronaldo, Benzema and Higuaín are just fine, so Mourinho will only need to choose between his two strikers. Taking into consideration that Borussia Dortmund's game is just around the corner, Real Madrid's coach could start Higuaín to see if the Argentinian striker is back in scoring form.
Mourinho himself revealed in Friday's press conference that it wouldn't surprise him to see one or two more players going down in these next few days. They haven't had the time to recover properly, but Mourinho will certainly have that in mind. That way, the starting lineup against Celta could be much different from the one against Borussia. It's key to avoid injuries. But it's also very important t keep winning.