Gareth Bale is coming to the end of his most frustrating season at Real Madrid

Uefa Champions League final: Juventus v Real Madrid Date: 3 June Venue: Principality Stadium, Cardiff Kick-off: 19:45 BST Coverage: Commentary on BBC Radio 5 live, text commentary, report and reaction on BBC Sport website

Real Madrid are playing in the Champions League final in Cardiff on Saturday - but Gareth Bale looks set to miss out against Juventus in his home city.

Wales forward Bale has been out with a calf injury for the past six weeks and, although he has now returned to full training, the former Tottenham player admitted he has not fully recovered from an ankle operation earlier in the season - and he also believes that caused the latest problem.

With the team's other 10 places more or less set in stone, the debate about whether Bale or Isco should be named in Zinedine Zidane's starting line-up has been the talking point in Spain in the build-up to Saturday's final, in which Real could complete their first league and European double since 1958.

And more significantly, it has become much more than a debate about this game, with Bale's longer-term future at the Bernabeu under more scrutiny than at any other time since he arrived from Tottenham for a world-record fee four years ago.

Writing in Marca on Monday, for example, Roberto Palomar headlined his article: "And what if selling Bale isn't such a bad idea?"

He claimed that "in time, his absence stops being a problem" and also argued that, for Real fans, the sight of Isco, Marco Asensio or Nacho watching from the stands is "more painful" than the absence of Bale, who "doesn't even provoke nostalgia".

And he concluded it might not be a bad thing if an English club, "fresh from failure and with hot pockets", manages to prise the 27-year-old away from the Spanish capital.

So is Bale's time at Real Madrid really coming to an end?

Why 4-4-2 adds up to problems for Bale

At 8.30pm on Tuesday, 7 March, Real were in trouble. They were 1-0 down at Napoli at half-time in the second leg of their Champions League last-16 tie having been outplayed in the opening period and knowing that conceding again would send them out.

Zidane took decisive action, abandoning his preferred 4-3-3 formation and reverting to a 4-4-2, pushing Bale back into a deeper position on the right of midfield.

The intention was to put an extra body in midfield and deny Napoli the space they had been finding so easily - and it worked. A header from Sergio Ramos put Real back in control of the tie and they ended up 3-1 winners on the night, progressing easily.

That game in Italy was not the first time Zidane had veered away from 4-3-3 - he had regularly experimented with several shapes - but it was perhaps a turning point because he has rarely returned to it since.

At first, Bale was able to keep his place in the team as a winger in a fairly conventional 4-4-2, but that approach wasn't satisfactory because it meant Luka Modric or Toni Kroos playing out position on the other flank.

And during Bale's recent absence, Zidane has made another tweak by introducing a narrow midfield diamond, with defensive-minded Casemiro at the base, Modric and Kroos on either side and Isco at the tip.

It has worked extremely well. The midfield quartet have exerted far more control over possession, Isco has pushed forward to support Karim Benzema and Cristiano Ronaldo, and full-backs Dani Carvajal and Marcelo have still provided plenty of width.

Although it is too early to tell whether Zidane has decided to abandon 4-3-3 for good, Real have played their most convincing football under his management with the 4-4-2 diamond - a formation it is difficult to see Bale fitting into easily.

'Greatest injustice in memory' - the battle for places

Bale trained with his team at an open session on Tuesday - but has not played since 23 April

While Bale may struggle to adapt to the new system, it has been tailor-made for Isco to finally start to fulfil his undoubted potential. The Spain international and Ronaldo have been Real's best players for the past few weeks.

Isco's technical ability, graceful style and good-humoured personality have always made him extremely popular with Real fans, who can be heard singing the 25-year-old's name far more regularly than Bale's.

Now there's overwhelming support for the opinion that he should start ahead of the Welshman - not just this weekend, but for good.

An article in Marca claimed it would be "the greatest injustice in memory" if Isco wasn't picked on Saturday, while a piece in El Pais underlined the Spaniard's greater suitability for the congested spaces of a midfield diamond - with the headline 'Footballer Isco; player Bale'. external-link

Perhaps of even greater concern for Bale is that he is not even guaranteed to be the first option from the bench.

Zidane is blessed with an extraordinary depth and variety of talent in the attacking midfield and forward departments, with Marco Asensio, James Rodriguez, Alvaro Morata and Lucas Vazquez also pushing hard for more minutes after impressive seasons.

In the long term, the rise of Asensio could be the biggest threat to Bale's status. The 21-year-old winger is regarded as one of Spain's hottest rising stars, and he was personally recommended to the club by national hero and fellow Mallorcan Rafael Nadal, the 14-time Grand Slam-winning tennis player.

Asensio showed his game-changing abilities with a superb solo goal in the quarter-final victory over Bayern Munich, and from now on he will get more than the 12 starts he has been granted this season.

As they play in the same position, it is easy to envisage his extra playing time coming at Bale's expense.

Isco's golden run of form 15 April: Scores two brilliant goals, including a last-minute winner, to secure a vital 3-2 win at Sporting Gijon 26 April: Makes headlines with some outrageous skill to set up Lucas Vazquez to score at Deportivo La Coruna 10 May: Nets the vital away goal at Atletico Madrid to secure Real's place in the Champions League final 17 May: Provides two brilliant assists for Cristiano Ronaldo to set up a 4-1 victory at Celta Vigo 21 May: Conjures another perfect pass for Ronaldo to convert in the title-clinching win at Malaga

'Confidence in him is declining'

Bale's recent absence was not his first and there is a strong sense frustration is growing over the frequency of his injuries.

Since arriving in Spain four years ago, Bale has had 16 spells on the sidelines and Alfredo Relano, editor of newspaper AS, is one who thinks the Wales international's fitness problems have let the team evolve without him.

"He has lost a lot of games with injuries and in the meantime new and very good players have emerged," Relano told BBC Sport.

"I think some of the club's confidence in him is declining. Florentino Perez signed him with the idea he would compete with Neymar for future Ballon d'Or awards, but we're already starting to see that's not going to happen."

Bale's troubled season Bale has not played since he limped out of the 3-2 El Clasico defeat by Barcelona on 23 April The Welshman suffered a recurrence of a calf injury that was diagnosed as a grade-two tear The 27-year-old also missed almost three months of the season after ankle surgery in November And he was sent off for the first time in his Real Madrid career when he kicked out and pushed Las Palmas' Jonathan Viera in March

If that's true, it would be a significant development. Bale has always been perceived as one of club president Perez's favourites, with former manager Carlo Ancelotti revealing in his recent book that one of the turning points in his relationship with Real came when Perez personally asked him to change Bale's playing position. external-link

However, Bale's injuries, the rise of Isco and Asensio and the impression that he doesn't fit into Zidane's new tactical formula, could force Perez into a rethink and make the player expendable rather than a guaranteed starter for the first time.

Relano believes that could even happen this summer, adding: "The club wants to sign Kylian Mbappe from Monaco and there are good offers for Bale from England. It wouldn't surprise me if he left."

Down… but not out

To put all the above into context, it must be remembered that, even in the fickle world of football, life at Real Madrid lurches rapidly from one extreme to the other like nowhere else.

It is only a few weeks, for example, since current flavour of the month Isco was reportedly on the verge of leaving.

A declining influence? Season Minutes played Goals Assists 2013-14 2,943 21 15 2014-15 3,409 15 10 2015-16 2,384 19 12 2016-17 1,921 9 3

Bale offers qualities nobody else at the club possesses. He is arguably the squad's best crosser, ranks alongside Ronaldo in his ability to attack balls into the middle and nobody can match his pace and power on the counter-attack.

Zidane is a strong advocate of an extreme rotation policy, consistently using all the players at his disposal rather than repeating the same starting XI. So even if Bale is no longer untouchable, he can still have a big role.

Bale, to his credit, has made it clear he will fully understand if Zidane leaves him out of the team on Saturday, refusing to put his coach under public pressure to pick him.

Amid all the negative talk, perhaps the most accurate assessment came from Jose Felix Diaz in Marca. He argued that Bale's return from injury is a solution rather than a problem and gives Zidane an extra "card up his sleeve".

Bale probably won't start against Juventus, but that does not necessarily mean his Bernabeu career is over.