Spain's 'Next XI' could revolve around Saul Niguez, Jose Gaya, Inaki Williams

Although many of the players who delivered the 2008 Euros, 2010 World Cup and 2012 Euros remain on the scene for Spain, Russia 2018 is likely to be the last hurrah for that once-in-a-century generation. Since taking over as manager, former U-21 coach Julen Lopetegui has been gradually bringing through some newer blood to the setup, and within a couple of years a whole new, different team is likely to take shape.

Here's who might well form the core of Spain's next great team:

Kepa Arrizabalaga | Goalkeeper | 22 | Athletic Bilbao

The 22-year-old has established himself as the Basque team's undisputed No. 1 this season and looks to have everything needed to be a top-class goalkeeper. The Ondarroa-born youngster has gradually gained experience in loan spells at lower-tier Ponferradina and Real Zaragoza while being capped at all U-17, U-19, U-20 and U-21 levels.

Kepa got a first senior call-up during March's international break when veteran Pepe Reina stepped out injured, and he looks to have the long-term edge over Sevilla's Sergio Rico and Celta Vigo's Ruben Blanco as the next in line behind current first choice David De Gea.

Jonny | Right-back | 23 | Celta Vigo

Even die-hard La Liga fans might find themselves checking twice to see that Jonathan Castro Otto, more commonly known as "Jonny," is still young enough to play for Spain's U-21s. He's been a mainstay of Celta's recent success both domestically and in Europe, a real leader in the team at either full-back position despite having just turned 23. What he perhaps lacks in technical niceties he makes up for in commitment and doggedness in defence, while his tendency to pop up in the most unexpected places often adds a useful extra to the team's attack.

Jonny already has played 170 times at the senior level, scoring three goals, including a crucial strike as Real Madrid were eliminated from the Copa del Rey last January. He often has been compared to another former Celta right-back, Michel Salgado, who went on to play for Madrid and Spain with plenty of success.

Jesus Vallejo | Centre-back | 20 | Real Madrid (on loan at Eintracht Frankfurt)

The Real defender has been "scandalously good" this season on loan in Germany but it should be his last season away from the Bernabeu. Vallejo should become a senior star very quickly, with his composure on the ball and confidence in one-on-one situations, against even the paciest of attackers, already greatly apparent.

Powerful and athletic, Vallejo joined Madrid from Real Zaragoza in a €5 million deal in 2015, spending the following season on loan back at the Segunda Division club. He is expected to replace veteran Pepe as a first-team squad member at the Bernabeu beginning next summer, and he should quickly overtake his teammate Nacho Fernandez as first back-up for both La Roja and Los Blancos.

Jorge Mere | Centre-back | 19 | Sporting Gijon

The homegrown defender already has had almost three years as a first-teamer at El Molinon since breaking through at the end of the 2014-15 season. The Oviedo-born player has been a fixture through the youth ranks at the international level and is a certain starter at next summer's U-21 European Championships.

Though Gijon have been struggling toward the bottom of the table, Mere's tremendous potential has been clear regardless of some unfortunate mistakes. He looks ready to step up to a bigger club next summer whether or not the Asturians are relegated.

Jose Gaya | Left-back | 21 | Valencia

Gaya is the latest left-back off the production line that also produced Barcelona's Jordi Alba and Bayern Munich's Juan Bernat. And just like his predecessors, Gaya is small in stature but feisty by nature, both technically excellent and lightning quick.

Regular turmoil on and off the pitch at Valencia -- and the strange decision to sign and sometimes select Guilherme Siqueira in his position -- has affected Gaya's progress over the past couple of seasons, but he already has over 100 senior games for Los Che as well as appearances at all levels for La Rojita. At this point, what he really needs is a regular run in a settled team going in the right direction, whether at Mestalla or elsewhere.

Marcos Llorente | Defensive Midfield | 22 | Real Madrid (on loan at Alaves)

His father, great uncle and grandfather were all Madrid stars, and Marcos Llorente has long been talked about around the Estadio Santiago Bernabeu as a sure thing to make it for both club and country.

Even still, it's been a surprise how easily Llorente has taken to his first experience of top-flight football on loan at Alaves this season. The youngster has been virtually ever-present as the newly promoted side consolidated a place in mid-table and reached the Copa del Rey final.

An intelligent reader of the game, incisive passer and willing tackler, he's a natural in the "holding" role in deep midfield and will challenge Casemiro for a first-team place on his return to the Bernabeu next summer. In the long term, he seems the most likely replacement for Sergio Busquets in this key position for the national team.

Saul Niguez | Central Midfield | 22 | Atletico Madrid

If he were anything other than Spanish, he'd surely already be one of the pillars of a national team, nearing a half-century of full caps. But given the competition with Busquets, Thiago Alcantara, Andres Iniesta and his teammate Koke, the Atletico Madrid midfielder has remained with the U-21s, who he will captain at June's Euros in Poland.

Atletico coach Diego Simeone has at times used tough love to get the best out of a player who has many of the attributes that made his current manager a world-class player. An all-rounder who covers every blade of grass, Saul combines tremendous physical presence with a knack for spectacular individual goals at crucial moments against the likes of Real Madrid and Bayern Munich.

Such a talent already has brought interest from Europe's richest clubs, and it remains to be seen how long Jorge Mendes' client remains in Madrid. By Russia 2018, though, he's sure to be a member of the senior Spain squad.

Dani Ceballos | Central Midfield | 20 | Real Betis

Another player much talked about before he had been seen too often, the Real Betis playmaker has emerged this season as a star who will soon outgrow his surroundings at the Estadio Benito Villamarin.

During his first two seasons around the first team, Ceballos mixed some startling flashes of skill with even more outrageous losses of control, raising questions over whether he had the temperament to make it at the top level. But so far this term, especially since former Spain midfielder Victor took over as verdiblanco coach, the cheeky youngster's performances have shown a new maturity.

Still only 20, Ceballos has the imagination and athleticism to run games from midfield, and reports that Atletico Madrid are preparing to meet his €15 million release clause this summer look well founded.

Mikel Oyarzabal | Right Wing | 19 | Real Sociedad

Possibly the only positive thing to come from David Moyes' time as Real Sociedad coach was a debut for Oyarzabal, 18 at the time, although it took Eusebio Sacristan replacing the Scot a few weeks later for his senior career to really take off. Barely out of the txuri-urdin first team ever since, the Eibar-born winger already has become one of the key players in the side, generally playing wide right and cutting inside, which allows him to show off his dangerous shot, creative eye for an assist and decent ability in the air.

There was even senior international recognition in a pre-Euro 2016 friendly last summer, around the time neighbours Athletic were trying very hard to whisk away the most promising teenager in the Basque Country. Oyarzabal signed a new and improved contract at the time and is already ahead of the career arc previously taken by Antoine Griezmann, which suggests he has the potential to go a long, long way.

Inaki Williams | Striker | 22 | Athletic Bilbao

Born in Bilbao to a Ghanaian father and a Liberian mother, Williams has long been viewed as someone likely to make a big impact. A prolific goalscorer for Athletic's youth team and B-sides, he averages a healthy one goal in every six La Liga games. These strikes have included a number of crackers, such as when he marked his 100th senior game by netting in the recent 2-0 derbi win over Real Sociedad. That was then followed by an outstanding display of pace and directness as he drove again and again past a hapless Marcelo as Real Madrid just got out of San Mames with a 2-1 win earlier this month.

Although played mostly as a wide attacker to date, Williams is clearly earmarked to replace Aritz Aduriz as Athletic's next No. 9 ... unless suitors (who have reportedly included Juventus, Liverpool and Everton) can entice him away. His most recent contract includes a €40 million release clause, a fee someone is sure to offer if his development continues.

Marco Asensio | Winger | 21 | Real Madrid

Even among the crowd of talented playmakers at the Bernabeu, Asensio has stood out this season as the real thing. Madrid moved while Barca dithered in December 2014 to sign him, 18 years old at the time, for what now looks an absolute bargain price of €3.7 million. He continued his progress on loan back at hometown club Mallorca and then at Espanyol; this season, he stepped up seamlessly to Madrid's first-team squad and became the first Blancos player ever to score on his debut in four different competitions.

The quality of many of his goals, such as the 30-yarder into the top corner during last August's European Supercup, showcase the youngster's technique and audacity. Given his liking for cutting in from the left wing before shooting on either foot, Asensio looks the most natural long term successor to Cristiano Ronaldo in the starting XI, and he clearly seems comfortable in such company too.