Lionel Messi
Any discussion about FC Barcelona's prospects for the coming season is bound to be conditioned by last week's news that Lionel Messi has left the club after Barca were unable to fit his new contract into their wage structure.
The news not only brings an end to Messi's 21 years at the club, robbing Barca of their top scorer and assist provider in one go, but is also a further blow to the club's troubled finances.
It is also a massive blow to Barca's morale, but if coach Ronald Koeman is able to organise his team well and the team is not badly affected by injuries, it may not be a fatal one.
Koeman continues for a second year at the Camp Nou after a difficult first campaign and probably kept his job thanks to his excellent work with young players, such as midfielder Pedri, central defender Ronald Araujo and midfielder Ilaix Moriba, who broke into the side at the end of last season.
Araujo looked to be the solution to the club's defensive issues, but suffered too many injury problems, while Ilaix's brief career now threatens to be derailed by disagreements over his new contract which has seen him relegated to the B-team.
Meanwhile, Pedri's season only finished on Saturday after the Olympic Games final put an end to a campaign that saw him play an incredible 73 matches. He will need a holiday before even starting a pre-season and will miss at least the first three games of the new campaign, while Koeman will be crossing his fingers the youngster doesn't suffer from burnout in the coming months.
Although Barcelona president Joan Laporta has adopted a 'low cost' transfer policy over the summer, Barca appear to have signed well, with strikers Sergio Aguero and Memphis Depay joining on free transfers. There will be doubts about 33-year-old Aguero's fitness, but not about his goalscoring ability, while Depay and Koeman have already worked successfully together with the Dutch national team.
Antoine Griezmann will have to step up in the wake of Messi's departure, but he enjoyed a decent season under Koeman last year and an attack of Aguero, Depay and Griezmann should worry most sides.
Perhaps the key thing will be how and when Ansu Fati returns after missing nearly all of last season with his knee ligament injury, which has taken much longer than expected to recover from. If Ansu gets back to fitness and the form he showed before his injury, then Barca will hope he can take on the difficult mantle of being the 'new Messi'.
Barca have also signed well in defence, with central defender Eric Garcia returning from Manchester City and wing-back Emerson moving from Real Betis.
Garcia is a classy player who the club see as the long-term replacement for Gerard Pique, while Emerson is a strong addition down the right, who will be especially important if Koeman continues to play with three central defenders.
Elsewhere, Jordi Alba and Sergio Busquets remain key players, although Koeman will hope that they can ward off the advancing years for another season, while Frenkie de Jong will need to continue progressing in midfield.
Meanwhile, with Miralem Pjanic likely to leave before the end of August, the pressure will be on Pedri to reproduce last season's form, and maybe this could be the year Riqui Puig finally breaks into the team, while 18-year-old Yusuf Demir has also impressed in pre-season.
With Barca clearly at a delicate moment after Messi's shock departure and fans not entirely convinced by Koeman, much could depend on how Barca start the season. If they start well, there is no reason they can't challenge in La Liga against rivals who look no stronger than last year, but if they get a poor start, expect to hear knives being sharpened at the Camp Nou.
