Real Madrid begin their official season on Saturday, August 22, at home against Espanyol, with a scheduled 21:30 CET kickoff. For US coaches that translates to 3:30 p.m. ET and 12:30 p.m. PT, an afternoon watch rather than a late night. It is Jose Mourinho's first competitive match of his second spell in charge, and the headline going in is not who scores. It is who defends.

The problem is the middle of the back line. Spanish reporting frames this as the same issue that dogged the coaches who came before Mourinho in recent seasons, including Carlo Ancelotti, Xabi Alonso and Alvaro Arbeloa in their various roles. Injuries and turnover have left Madrid thin at center back, and the opener arrives before the group is fully settled. It is a familiar sight at this club: enormous resources everywhere on the field and a nagging shortage of healthy, in-form central defenders.

That combination, a marquee coach and a soft spot at the back, is a useful thing to hand your players before a big game. It is a reminder that even the richest team in the sport can be stretched thin at one position, and that squad depth is not the same as squad balance. A roster can look loaded and still have a hole exactly where you cannot afford one.

Why the center of defense is the hardest spot to cover

Center back is the position where you cannot improvise your way out of trouble. A creative midfielder can drop deeper or drift wide. A striker can be replaced by pace or hold-up play. But two center backs who do not know each other's habits, or a converted full-back filling in, will get exposed by a single well-timed run. The partnership is built over months of reps, not days, and that is why Madrid's shortage matters more than the same number of absences would in another zone.

There is also the matter of Espanyol arriving with belief. One of their new central defenders publicly said he is ready to face Madrid, the kind of quote that tells you the underdog is not planning to sit back and admire the hosts. A team that fancies its chances of getting at a patched-together back line will test it early and often.

What Mourinho actually has to decide

The coaching decision here is about pairings and protection. If Madrid are short on natural center backs, Mourinho has choices: play a young academy defender, slide a full-back inside, or drop a midfielder to screen the two he has. Each option changes how the whole team defends. A screening midfielder buys the center backs time but pulls a passer out of the buildup. Playing a kid means trusting concentration under pressure that has not been proven at this level.

For your own team, the lesson is preparation, not panic. When you are missing a center back on a Tuesday, do not just plug the nearest body into the hole and hope. Decide first how you want to defend without that player, then pick the personnel to fit the plan. A back line that knows its job as a unit will outperform a more talented back line that has been thrown together an hour before kickoff.

Watch Saturday for how Madrid's defenders communicate on the first few crosses and set pieces. Early-season back lines betray themselves on organization long before they betray themselves on individual mistakes. If the two center backs are pointing, stepping and covering in sync, Mourinho solved his problem. If they are ball-watching, Espanyol will find the gaps.

Either way, the opener is a live case study in a truth every coach knows: you build a season from the back, and you cannot buy a partnership at the deadline.