Friday will see Vicente del Bosque call up a squad of players for two friendly fixtures against Italy and Romania, both played away from home, for what will be the last pair of games for the Spanish national team before the end of the season.
Thereafter it will be a series of games in the build up to the 2016 UEFA European Championships, meaning this is realistically the final opportunity to take a close look at names who have impressed this season, particularly in the four months since Spain's last get-together.
The manager isn't known for huge rotations in his squad, even with the plethora of options available to Spain, but this is one occasion he should be looking to bring in a few lesser-utilised players who have been standout individuals in La Liga and beyond, rewarding them for consistency as well as quality and because they can have a very real impact on the squad, starting with Atletico Madrid midfielder Saul Niguez.
Last chance to experiment
There's no question that aside from being a creature of habit, Del Bosque trusts his players to a fault. He isn't interested in dumping five or six from the established squad and replacing them at the last moment; this is a squad he has gently evolved since the Euro 2008 triumph, and they have gone on to further lift a World Cup and another Euro title.
He believes in them, not only technically and tactically but for their ability to mix with each other—previously a real problem for Spain—and to behave according to how the group dynamic best functions. That latter is, of course, a reason Diego Costa has previously sat out games, and there's no guarantee he'll travel to France at this stage, even if he is one of the three favoured forwards.
But this is the last chance. Opportunity knocks for Del Bosque, not to make wholesale changes but to make the two or three worthwhile additions that could make all the difference for Spain.
Covering key positions, adding a different blend of talents and having more competition for places could all have a profound effect on how far Spain go this time, even with that small number of alterations to the squad.
Regulars out of action
There will have to be some changes to the usual squad.
Santi Cazorla remains sidelined and isn't likely to play much of a part this season for Arsenal, so his chances of making the Euros seem slim. Diego Costa hasn't been suspended for an incident with Gareth Barry a week ago, but Marca reported he may miss the Spain games through injury instead.
In defence, the last squad saw Marc Bartra of Barcelona and Nacho of Real Madrid called up, but both have been peripheral figures, barely seeing any game time.
Elsewhere, Nolito is now fit again but has only a handful of games behind him since November. He's probably going to the Euros, but it's not certain he'll be involved this time. Add in irregular and inconsistent performances over the past couple of months from Isco, Pedro, Paco Alcacer and Juan Mata, and it's clear that Del Bosque's trust in players might end up being more of a defining factor than their actual performances.
Better call Saul
One player who simply has to be called up is Saul. There should be no argument on Del Bosque's part with it, for several reasons.
For starters, the 21-year-old has bossed La Liga since November, becoming an integral member of Atletico Madrid's starting XI as they fight for the title and have reached the last eight in Europe. His all-round game has come on plenty, but it's his consistency that has impressed the most.
Tactically, he is well-suited to any role in midfield, having the physicality and the speed to make up ground defensively, while also being technically proficient and adept at getting into the box, finding searching passes between the lines and—perhaps most importantly in a Spain side that doesn't score too many goals—getting himself into the box to aggressively attack crosses and through passes.
From a more practical point of view, Saul's inclusion in a tournament squad should be a no-brainer once his technical attributes are appreciated: He can fill any role in midfield, holding, attacking or wide, plus he can also fill in as a central defender or play just off the main striker. Where limited names can be taken, such a trait is too much of a bonus to ignore.
Diego Simeone doesn't play individuals without them fully meriting their spot, much less let them break in and take someone else's position.
Saul has done that and been an ever-present in La Liga since winning himself a place, and he has to be the first new name on Del Bosque's squad list.
A year ago, Spain's trio of goalkeepers looked set. Iker Casillas remained No. 1, albeit against many onlookers' wishes, while David De Gea was the backup, pushing for game time with tremendous form. The third-choice goalkeeper had changed around plenty over the previous 12 months, but Sergio Asenjo's form for Villarreal made him an established and correct choice for the third stopper.
Now, it's all change. Asenjo hasn't played this term due to an ACL tear, Casillas' form continues to deteriorate and De Gea looks a certain to be the No. 1 at the Euros.
The manager told Marca that Casillas would still be a good influence as a substitute at the Euros, a situation that probably suits all involved, but it still leaves the decision of the third choice.
Sergio Rico of Sevilla has been that man of late, a quality young goalkeeper but full of inconsistencies and errors at times. It's perhaps worthwhile looking elsewhere, since there are a few names in good-to-great form this season.
Antonio Adan of Real Betis has been closer to the good end of the scale, impressing in La Liga and especially against the bigger sides, while West Ham United's Adrian has been close to great, just as he was last season, in fact. The Hammers stopper perhaps suffers from being out of sight, out of mind, but he must be a consideration at least.
One of the most spoken-about players in La Liga who has been continually overlooked by the Spanish national team is Aritz Aduriz. By now, there have been reams written about his exploits this season, and Del Bosque has been forced into answering questions about him on multiple occasions, but it's still worth pressing home the point.
Aduriz has 17 goals in La Liga, more than any other Spaniard, and 30 in all competitions. At age 35, it's Euro 2016 or nothing for the Athletic striker, but his goalscoring record indicates he'd bring something worthwhile to the team.
The Basque man has netted at a rate of a goal every 125 minutes this season, in all competitions, comparing favourably to positional rivals Costa (201 minutes), Alcacer (223) and Alvaro Morata (255). In pure numbers, Aduriz's 30 strikes is double that of Costa's 15, with the other two trailing behind on 11 and eight, respectively.
With that in mind, it's quite some moment for Morata to have put in his best game of the season on Wednesday night as Juventus almost beat Bayern Munich in the UEFA Champions League.
There are others. They'll be on the fringes of Del Bosque's thinking for various reasons, but their form warrants consideration nonetheless.
Barcelona's Sergi Roberto has had an excellent campaign, playing almost as much game time as Andres Iniesta and offering as much versatility as Saul does—Roberto has played both full-back roles, wide in attack and three central midfield roles for Barca this term.
In defence, with Bartra and Nacho surely not the best choices due to lack of game time, Villarreal's Victor Ruiz should be a consideration—but his own poor couple of performances recently couldn't have come at a worse time. Even so, he has been consistent, aggressive and impressive all season long until now, and Spain need a third centre-back. Raul Albiol isn't the answer, and Inigo Martinez hasn't done enough.
Saul may fill the role of chief backup to guaranteed starter Sergio Busquets, but Ignacio Camacho is another potential name to consider...if he can stay fit and on the pitch.
Del Bosque, or any Spain manager in future, will never have a paucity of options to choose from, but regeneration is a key part of keeping an international squad competitive, especially when there are players who have proved they deserve to be involved and will have an obvious positive impact on the squad.
Expect Spain's Euro 2016 squad to contain mostly familiar faces, but this week at least, Saul and Aduriz are must-have inclusions even if nobody else breaches the high walls around the main group.