The season is over, but the transfer business is only just beginning for Europe's top clubs. ESPN FC's club correspondents discuss who will be in the firing line in the summer window.
BARCELONA (Sam Marsden)
Rough budget: President Josep Maria Bartomeu says the club start every summer with the same budget: €60 million plus whatever they can bring in from sales. With €100m already looking earmarked for Atletico Madrid's Antoine Griezmann, they're going to need to be astute with their sales if they want to strengthen in other areas.
Who should the club buy?
A deal for Griezmann appears increasingly likely, which will leave coach Ernesto Valverde with a nice problem: fitting the French forward into the team with Philippe Coutinho, Ousmane Dembele, Lionel Messi and Luis Suarez. Elsewhere, midfield reinforcements will be needed with Andres Iniesta leaving and Ivan Rakitic, Paulinho and Sergio Busquets all around the age of 30. There's a deal in place for Gremio's Brazilian midfielder Arthur, but it may not be finalised until January. Barca are also looking at centre-backs. Gerard Pique is 31, Javier Mascherano has gone, Samuel Umtiti could follow and there's not complete faith in Thomas Vermaelen and Yerry Mina. Sevilla's Clement Lenglet and Ajax's Matthijs de Ligt have been watched extensively.
Who should the club sell?
Andre Gomes and Paco Alcacer, two summer signings from Valencia in 2016, have not been able to make their mark at Camp Nou and both will be sold for the right price. Aleix Vidal's time also looks up and Barca will hope to fetch north of €10m for him, too. Denis Suarez and Lucas Digne could also be let go, although it's not as clear-cut. Denis has shown glimpses of his talent and is desperate to stay, while Digne is the only alternative to Jordi Alba at left-back. He should only be sold if the club feel they have an academy player who can take on his role.
Biggest transfer lines to follow: Will Griezmann, after all the speculation, finally sign? Will Umtiti sign a new contract or will a club pay his €60m release clause? Catalunya Radio have claimed that the club might listen to offers for Luis Suarez, who is now 31. They wouldn't, would they?
REAL MADRID (Dermot Corrigan)
Rough budget: Real Madrid's most recent accounts showed a "cash balance" of €178m. It is also four years now since their last Galactico purchase, and a number of ex-youth team players will be sold this summer as usual. So it looks like there will be plenty of money to spend if the right players become available.
Who should the club buy?
Zinedine Zidane's squad is very short of cover in defensive areas, with a reliable centre-half and back-up right-back the most obvious gaps. They will also need at least one goalkeeper, whether an experienced replacement for Keylor Navas or young understudy for the current No. 1. And a new young pacy forward is required for when the club's big names are rested at intervals through the season.
Who should the club sell?
Recent weeks have brought the biggest signs yet that Gareth Bale will accept his time in Spain is over, and the Welshman is probably the most valuable asset that coach Zidane would be willing to let go. A bid of €60m plus for midfield understudy Mateo Kovacic might also be difficult to turn down, while Madrid's hierarchy would be delighted to get back the €16.5m spent on young playmaker Dani Ceballos last summer.
Biggest transfer lines to follow: Madrid president Florentino Perez's continued pursuit of Neymar looks set to continue, possibly through the World Cup and beyond. Perez's other long-term target David De Gea is sure to feature on the front page of Marca in the coming weeks. A good World Cup for Harry Kane, Robert Lewandowski, Timo Werner, Kylian Mbappe, Eden Hazard would also see them return to the covers of the local Spanish sports press.
ATLETICO MADRID (Dermot Corrigan)
Rough budget: Atletico wheel and deal every summer, and this year's totals for ins and outs are likely to again be roughly equal in value. How much money is eventually spent depends almost entirely on whether Griezmann especially and Jan Oblak are persuaded to remain at the club. Should either, or both, move on, then coach Diego Simeone and sporting director Andrea Berti will have plenty to spend.
Who should the club buy?
The exits of two players last January, then three more in February for China, left Simeone with a very short senior squad. They need a new back-up goalkeeper for sure, and cover in most other positions. Celta Vigo's versatile full-back Jonny Otto is rumoured to have already agreed to join, while Villarreal holding midfielder Rodri could return to the club which let him go as a teenager. Another physical striker to replace departing veteran Fernando Torres should also be on the list.
Who should the club buy sell?
Given numbers are so tight, Simeone will not be keen to sell anyone unless he gets plenty of bodies in first. The most likely squad player to leave would be 23-year-old centre-back Jose Maria Gimenez, but still behind Stefan Savic for regular starts for much of 2017-18. If funds need to be raised -- especially if Griezmann and Oblak both stay -- then the longtime Manchester United target is the most likely to leave.
Biggest transfer lines to follow: Griezmann's future will determine all the club's other transfer business this summer. Should the France international leave, a top quality replacement will be required. The most exciting possibility would be Juventus' Paulo Dybala, who Simeone clearly likes, while Paris Saint-Germain's Angel Di Maria and Edinson Cavani have also been linked.
JUVENTUS (Ben Gladwell)
Rough budget: There is no real budget, other than to say Juve have made bargain-hunting into an art form. Emre Can could well be the next free transfer arrival at the Bianconeri, but they showed with the €94m signing of Gonzalo Higuain two summers ago that they are not afraid to spend big either. Expect spending of up to €100m, although they would not be afraid to spend more as the resources are there.
Who should the club buy?
Can has been identified as the club's No. 1 target and would add further depth to the midfield, although a new full-back is the priority, with Stephan Lichtsteiner and Kwadwo Asamoah both leaving, and Alex Sandro also set to be sold. Man United's Matteo Darmian would be an ideal target, given his versatility to play on either side of the defence, while Bayern's Juan Bernat is another reported target. Up front, Chelsea's Alvaro Morata would be welcomed back with open arms, giving coach Massimiliano Allegri greater choice up front, alongside Higuain and Paulo Dybala.
Who should the club sell?
Sami Khedira is still under contract and this could be the last time Juve could command a fee for a player who has openly admitted he fancies a new adventure. Sandro also appears unsettled and Juve have repeatedly stressed that they do not want to hold any player against their will. With Gianluigi Buffon leaving this summer, the club revealed they would be trusting Wojciech Szczesny with the No. 1 spot.
Biggest transfer lines to follow: The Can and Darmian pursuits are likely to be the main objectives, but both could be wrapped up well before preseason training commences. That would leave a more "surprise" swoop, which could be along the lines of Anthony Martial or even Paul Pogba. Morata may be one of those summer sagas which may end late on, when it cannot be ruled out that Juve will blow their remaining budget on a last-ditch big-name.
BAYERN MUNICH (Mark Lovell)
Rough budget: €100 million plus. Franck Ribery, Arjen Robben and Rafinha have all agreed to stay on for another season, but with new coach Niko Kovac coming in this summer, there could be some changes.
Who should the club buy?
If Lewandowski leaves, Bayern should pull out all the stops to bring in Germany international striker Timo Werner from Leipzig. And if Bayern do decide they want to do business with Real Madrid on Lewandowski, look for the German champions to include the likes of Karim Benzema and Gareth Bale in the deal as makeweights. Bale's advisers have just opened an office in Munich -- let the speculation commence.
Who should the club sell?
What to do with Lewandowski? Despite constant speculation, Bayern have maintained that their prolific top scorer is not for sale, pointing to his contract until 2021. However, his change of agent to Pini Zahavi indicates he has his sights on a move over the summer. Real Madrid are long held to be his favourite destination, but PSG, Chelsea and Manchester United have also been mooted as possible destinations for the sulking striker.
Bayern might be prepared to do business on Jerome Boateng as they are well-catered for in central defence with Mats Hummels, Niklas Sule and the up and coming Lukas Mai. There would be no shortage of takers for one of the best centre backs in the game (when fit) and the club could expect to make serious money.
Leon Goretzka's arrival could see Arturo Vidal depart. The Chilean was never likely to leave while Jupp Heynckes was at the helm, but with his mentor leaving, Bayern may see it as a last chance to recoup the €35m paid to Juventus in 2015.
Sebastian Rudy and Juan Bernat remains bit-part players and could move on, while Bayern will have to take a massive loss if they want to get Renato Sanches off the books. After a disappointing loan spell at relegated Swansea, Sanches' drop in form could see him return to first club Benfica.
Biggest transfer lines to follow: Provided they steer clear of injury at the World Cup for Poland and Germany respectively, Lewandowski and Boateng will be the ones to watch over the summer. Strongly linked with Chelsea and Manchester United in the past, Vidal may also attract some attention provided he overcomes his latest knee injury.
BORUSSIA DORTMUND (Stefan Buczko)
Rough budget: €80m. But before making additions and building a new squad, Dortmund need to weed out a bunch of players that have disappointed or are simply not up to the required level. The club have a tricky summer ahead as their squad needs a big overhaul after a season which showed a lack of team chemistry was clear.
Who should the club buy?
A backup goalkeeper for the retiring Roman Weidenfeller, who they seem to have found in Augsburg's Marwin Hitz. Another centre-back will also be required and Ajax's Matthijs de Ligt seems like a solid choice. Dortmund are also looking for new full-backs for the ageing Marcel Schmelzer and Lukasz Piszczek -- possibly Juventus' veteran right-back Stephan Lichtsteiner. They will also have to add some physicality in defensive midfield without conceding technical ability and have already laid eyes on RB Salzburg's Diadie Samassekou. Furthermore, BVB have to find a replacement for Pierre-Emerick Aubameyang, who left for Arsenal in January. They may attempt to sign Michy Batshuayi from Chelsea, who proved to be a clinical finisher on loan in a yellow shirt. And, once the most important positions are covered, they could also pursue another attacking midfield in David Neres.
Who should the club sell?
They should cut their losses on Andre Schurrle, while Ousmane Dembele's replacement, Andrij Yarmolenko, has also tanked after a bright start. Albeit being an important character in the dressing room, Nuri Sahin's best days are past him and he takes up too much room on the wage bill for too little quality. Centre-back Sokratis Papastathopoulos has been extremely error prone in his decision making. Sebastian Rode, Jeremy Toljan, Gonzalo Castro and Erik Durm are also out of their depth.
Biggest transfer lines to follow: Lucien Favre's arrival to replace Peter Stoger means fun rumours like Mario Balotelli will be part of the noise. Their pursuit of a striker will most likely be the trickiest endeavour -- especially, if Chelsea are unwilling to sell Batshuayi, as they were already too late to sign Lautaro Martinez from Racing Club. A successful summer of incomings will first depend on whether Dortmund are able to get rid of the deadwood, as BVB's finances are finite.
PSG (Jonathan Johnson)
Rough budget: Depending on the outcome of UEFA's financial fair play (FFP) investigation regarding last summer's exorbitant spending on Neymar and Kylian Mbappe, expect PSG to have around €200m to play with. That said, depending on when UEFA announce their verdict, the transfer window might well have already been open for the best part of a month.
Who should the club buy?
The way that money is spent will depend largely on new manager Thomas Tuchel's potential formation, but PSG need a new defensive midfielder, new left-back options, another central defender (two if captain Thiago Silva leaves) and possibly a new right-back, as well as attacking depth. What the club's Qatari owners want is likely to be something shinier and more unnecessary than players to fill those positions of need, such as a new goalkeeper, and a more attack-minded midfielder. Sources say the club are keen on Buffon and the 40-year-old would bring some much needed Champions League experience.
Who should the club sell?
Thiago Motta will retire; Layvin Kurzawa has already been told he can leave; Thomas Meunier is talking his way out of the club; Yuri Berchiche has struggled to truly convince and Goncalo Guedes has half of Europe's elite knocking on PSG's door after an impressive loan spell with Valencia. Depending on FFP, Les Parisiens should have no problems raising funds, if needed.
Biggest transfer lines to follow: Manchester United's Paul Pogba could be a target and PSG's pursuit of a new goalkeeper, despite Alphonse Areola's more than adequate season, will lead them to Buffon. Whether the Ligue 1 giants stick or twist with Cavani as part of their plans alongside Neymar and Mbappe will be interesting, while skipper Silva and Angel Di Maria's futures are also unclear. Adrien Rabiot's contract extension talks with his current deal up next summer will be key.