The January transfer window is approaching, and the rumour mill is already buzzing. Teams have prepared their wishlists, looking to strengthen positions of weakness in order to be in the hunt for all possible titles come the end of the season.
With superstars like Alexis Sánchez, Mesut Özil and Leon Goretzka available for free at the end of the season, their clubs could potentially be looking to sell them in January to avoid the possibility of a loss of incredible talent for absolutely nothing.
Almost every top club requires reinforcements in positions that have let them down and have made even the best of the best look unconvincing at times this season.
Let's have a look at the positions that require back-up or replacements for Europe's top non-English clubs, as well as the players that each club should try and sign:
#5: Atletico Madrid
Positions that need strengthening - Attacking midfielder/Winger
Atlético Madrid have been one of the favourites to win the Champions League over the past few years. Their drop down to the UEFA Europa League, having finished third in their group this season, presents a worrying sign and indicates their need to change personnel to progress in future.
Los Rojiblancos have been unbeaten in the league so far but with six draws in 15 league games, they have not really been on song either. Although they have been solid defensively as usual, the problems stem from their attacking play.
The struggles of Atletico are clear. They have not been able to create a lot of chances inside the 18-yard box, with 49% of their shots coming from outside the area.
In comparison to league leaders Barcelona, who have taken 70% from inside the area, it's not a statistic to be proud of. They have struggled to regularly penetrate opposition defences this season, with both Antoine Griezmann and Kevin Gameiro yet to hit top gear.
An attacking midfielder or a winger are the positions Los Colchoneros need to fill. Diego Costa's return to the fore in January will definitely help the team in an attacking perspective, but they need a midfielder in the mould of Manchester City's David Silva - who can carve open defences with pinpoint passes and through balls into the forwards.
Ander Herrera (Manchester United) has been linked with Atleti, but he is a player who is more defensive in nature. Atletico should target either Iago Aspas (Celta Vigo) or Alexis Sanchez (Arsenal), both of whom have been linked to play at the Wanda Metropolitano.
Both players are blessed with pace and skill, while the duo also have the quality to start every game for Atleti. With that being said, Alexis will turn 30 next year and Aspas is already 30-years-old, which suggests neither can be relied upon as a long-term option going forward given their playing style.
This would provide them with a high-quality winger who can also play further forward, but the midfield position still needs to be addressed. A suitable acquisition would be Nabil Fekir (Olympique Lyon) who is looking to move away from the French club, and has been in fine fettle this season. With 11 goals, four assists and an average of 1.9 key passes per game in 14 appearances for Lyon, Fekir has proved that he is an excellent midfielder and a goalscorer too. He is a suitable candidate to provide Atletico with the attacking impetus that they require.
#4: Bayern Munich
Positions that need strengthening - Striker, Fullback
Bayern Munich have not had a smooth sailing season so far, with two defeats and two draws in the Bundesliga, as well as a humiliating 3-0 away defeat at the hands of PSG in their Champions League group stage fixture.
However, they seem to have turned things around, especially after exacting revenge on Les Parisens at home this past week. Jupp Heynckes' managerial appointment has helped revive the side, who are looking stronger with each passing game.
The fact that Bayern have struggled to reach their own lofty expectations can also be noticed from their scorelines - their highest scoring games were 4-0 and 5-0 at home against 14th-placed Mainz and 16th-placed Freiburg. In the past seasons, Bayern have ripped a number of opponents apart with consummate ease, as scores of more than five goals seemingly the norm in Germany. This season though, they have faltered in the attacking third as Robert Lewandowski is their only real consistent goalscorer.
A back-up striker, or even a two-forward strikeforce could work wonders for Bayern in future. There needs to be another player other than Lewa whom they can look towards to provide the goals, especially with the amount of minutes the 29-year-old plays every week during a gruelling campaign.
Timo Werner (RB Leipzig) has been linked with Bayern, and it's no surprise that they are scouting him. A very strong finisher, he can link up well with Bayern's attack. The fact that he's German makes this transfer more probable, given their knack of acquiring many of the country's first-team players.
Sandro Wagner (Hoffenheim) could reportedly complete a deal with Bayern soon, according to coach Julian Nagelsmann. The drawback is that he is already 30, which is not an ideal scenario. But Wagner may be content with being a second-choice option to Lewandowski, while Werner would prefer to play every week, this signing could prove useful in the short-term.
Another forward whose name has been circulated recently is Arsenal's Olivier Giroud.
Another position that requires further options is the fullback position. The left-back and right-back spots are generally fixed with David Alaba and Joshua Kimmich the first choice on either side. Rafinha is back-up but being the wrong side of 30, they need another quality fullback who can actively compete for a place in the starting line-up.
As a result, they can target impressive 22-year-old left-back Jose Luis Gaya (Valencia), who is reportedly under the radar of Barcelona, Real Madrid and Chelsea to name but a few European sides tracking his progress. Blessed with incredible pace and attacking ability, he could undoubtedly challenge Alaba for a starting berth.
#3: Paris Saint-Germain
Positions that need strengthening - Defensive midfielder
Paris Saint-Germain (PSG) bought touted future Ballon d'Or winners Neymar and Kylian Mbappe (season-long loan, future fee) for a mind-boggling fee of €402m this past summer. The deals were always going to be heavily scrutinised but after the dust has settled, it's increasingly clear that the Ligue 1 giants were completely sane in making their huge purchases.
PSG have been absolutely brilliant to watch this season. They battered Bayern 3-0 at home in the Champions League, finished top of their group and are also cruising in the league with a nine-point lead despite a surprise 2-1 defeat away against Strasbourg on December 2, their first loss of the league campaign.
Coupled with their loss against a Bayern side keen for revenge on matchday six, these results proved they are still a beatable side. They cannot afford to let their foot off the gas with the knockout stages fast approaching, as a showdown with holders Real Madrid awaits in the round of 16.
Looking at the squad, there seems to be no lack of depth whatsoever. Their defence has been good on most occasions, the midfield has regularly been doing its job well and the attack has been sensational, creating a record for the most number of goals scored in the group stage of the Champions League (25 goals in six games).
They do not lack the players needed to win all trophies this term, either. The only position in which they may have a problem in future is the defensive midfield role. Adrien Rabiot has played very well there throughout this term, with Thiago Motta on the bench, but the 22-year-old is more naturally suited to a free roam role further forward. Motta is the typical ball-winner in midfield but is approaching the end of his career, prompting the need to replace him with a younger defensive midfielder.
Although all the rumours point towards signing another attack-minded player, they should sign someone in the mould of Idrissa Gana Gueye (Everton) or Ander Herrera (Manchester United), who are two of the Premier League's best defensive midfielders according to statistics.
Both are not guaranteed regular minutes at their current clubs, meaning PSG could pounce on the opportunity to seal the deal while potentially offering higher wages too. 25-year-old William Carvalho (Sporting Lisbon) is another player they could target.
#2: FC Barcelona
Positions that need to be strengthened - Attacking midfielder, Winger
Barcelona have had a very good start to the season, the only team to be unbeaten in all competitions this season. They sit pretty at the top of the table, five points clear of second-placed Valencia and they got through to the Champions League knockout stages by topping their group too.
Even though the results have come, there have been many inherent difficulties for this Barcelona side. They have only scored five in just one game thus far, against Espanyol at home. Most of their other wins have not been comfortable, even 3-0 wins over Girona and Leganes were unconvincing.
Their 1-1 draw with Valencia recently, which saw a Lionel Messi goal wrongly ruled out, was arguably their best attacking performance to date. The 3-0 victory over Juventus was a fantastic display too, with Messi magic taking centre-stage. There lies their problem, as many faults with the team are often hidden by Messi and his individual brilliance in focus.
Since Neymar's departure, Lionel Messi has had possession of the ball a lot more in every game. He has become the primary playmaker, dribbler, chance creator and goalscorer for the club. That's a lot of responsibility, isn't it?
This is where Barcelona are lacking compared to some of the other teams, like Manchester City for instance. Suarez has been in indifferent form so far, scoring only seven league goals and struggling for consistency in the final third.
As a result, the burden has fallen on Messi's shoulders, which also saw his longest goal-drought in a Barca shirt (six games without scoring). They need players who can take up more attacking responsibility and those are the players they need to target in January.
The positions that Barcelona need to look at are attacking midfielder and winger.
Andres Iniesta seems to back to nearly his enthralling best, but his legs are failing him with injuries popping up regularly, and an inability to complete full 90 minutes on the pitch means that Barcelona require a world-class replacement.
Philippe Coutinho (Liverpool) has clearly been Barcelona's first-choice, with their transfer attempts becoming public knowledge in the summer months. Rumours suggest they will be back with another massive bid, this time in the region of £130m, and rightly so. Coutinho is a top-quality midfielder and at 25, is still yet to reach his peak years.
With incredible close control, an eye for a pass and good goalscorer himself, he is the perfect remedy that Barcelona need. His transfer in January would mean that he is no longer able to play in the Champions League this season, having already represented the Reds in their group stage fixtures, but he may be willing to give that up in order to secure his dream move.
Other targets for Barcelona include Mesut Ozil (Arsenal) and Angel di María (PSG), the latter confirming that Barca wanted him in the summer. Both players are world-class and could be valuable additions to the squad, but their Real Madrid history may turn out to be the factor which will not allow a move to the club.
Winger is another position they need to get reinforcements for, with Gerard Deulofeu having made a lukewarm impact since rejoining Barcelona from Everton. Ousmane Dembélé is stepping up his recovery from a lengthy injury and still deserves his opportunity centre-stage, but they need to be prepared with another winger of the same calibre who can challenge the young Frenchman for a place in the starting eleven every week.
PSG's Julian Draxler and Nabil Fekir have both been linked to Barca in recent months. Acquiring either of the pair would help improve Barcelona's attack drastically - they have both shown quality for their respective clubs that the La Liga giants would greatly benefit from, but have struggled to see enough of from their existing players.
#1: Real Madrid
Positions that need strengthening - Striker, Winger
The biggest surprise of the 2017/18 season so far has been Real Madrid's form.
Coming into the season in a rich vein of confidence, having thrashed arch-rivals Barcelona 5-1 on aggregate in the Spanish Super Cup, many analysts believed it would be another clean sweep for Los Blancos this term.
But how things have changed so drastically since then. Having finished second in their Champions League group, while performing poorly against Tottenham, their punishment is a tricky tie against fellow European heavyweights PSG in the last-16.
The curious case surrounding Real is a difficult one to decode. They have almost the same squad, barring a few departures, who were all replaed with younger talents.
At present they are already eight points off top spot in La Liga, while they continue to drop points regularly against smaller sides themselves. Their home form is a worry, as they have struggled for consistency in matches - which they had no problems with last season.
The attack has struggled to garner goals, especially in the league. Ronaldo has four league goals, whereas nine in Europe's elite club competition which is inbalanced. With that in mind, mid-table sides like Malaga in Spain are considered stronger opposition than APOEL Nicosia - who the 32-year-old netted four against in two group stage fixtures.
Karim Benzema is clearly no longer at the peak of his powers as he struggles to make much impact in the majority of their games too. Toni Kroos has also been uncharacteristically poor this season. Giving the ball away cheaply on so many occasions, it is no coincidence that they struggle without the German's controlling nature in matches.
Gareth Bale's injury problems seem never-ending while Lucas Vazquez and Marco Asensio have failed to capitalise on first-team opportunities in the Welshman's absence.
Consequent to the above reasons, Real need to look at strengthening the following positions - winger and striker.
Eden Hazard (Chelsea) has been a long-term target for Los Blancos. He'd definitely fit right into the scheme of things, and his transfer can be funded by the sale of injury-prone Gareth Bale - who has continually been linked with a return to England.
An excellent dribbler who has averaged 4.5 dribbles per game this season, he can provide an exciting attacking front. The fact that he's not a player who is goal-hungry would alos benefit Ronaldo a lot, while acquiring his services could prove to be a masterstroke as Real look to get their season back on track.
Karim Benzema has not been up to the mark for a while now, and the need for a world-class striker is now more than ever. Borja Mayoral has done well whenever given the chance, but with the knockout stages approaching Madrid need an experienced and effective forward.
Pierre Emerick Aubameyang (Borussia Dortmund) has previously admitted that a move to Real Madrid would be a dream for him. Lightning quick, he would be an asset to their counter-attacking style of football and has been regularly linked in recent seasons.
Despite struggling to replicate his goalscoring efficiency this term in a struggling Dortmund side, he remains an option that the Spaniards may explore.
Another player they are reportedly scouting is the young German Timo Werner (RB Liepzig). Although fairly inexperienced, Werner has proven that he can do well under pressure with good performances for Germany in the Confederaions Cup this past summer. If they were to try and sign him, it would represent a gamble but one which could pay dividends in the coming years..