It's been a whirlwind couple of weeks in the European soccer universe, with teams attempting to cram a full offseason's worth of both transfers and transfer rumors into the shortest offseason ever. But as moves have become official, they have created a few particularly interesting position battles among the top teams on the continent. Here are a few of the most interesting, and most important battles on the docket, the outcomes of which could decide title races in Europe's biggest leagues.

(Note: the list below is not intended to be a comprehensive list of contenders, but a focus on teams with new-ish players and particularly interesting decisions to make. So the absence of Liverpool, for instance, isn't a suggestion that Liverpool won't contend in the Premier League this year.)

Jump to: Man City | Man United | Chelsea | Real Madrid | Barcelona | Bayern Munich | Borussia Dortmund | Juventus | Napoli

Premier League

Manchester City centre-backs

We'll start with one of last year's most definitive storylines. Manchester City allowed the most high-quality shots in the Premier League in 2019-20. Opponents averaged 0.144 XG per shot, the highest in the league, and while it's pretty common for a high-possession team to give up good looks because said looks are often coming in rare counter-attacking chances, City was still average at worst in this department when winning the title the year before.

There were a couple of reasons for this. First, the aging Fernandinho moved from defensive midfield to central defense, with new acquisition Rodri taking his place in the DM role. Rodri is brilliant from a pressure standpoint -- his 228 ball recoveries easily led the team -- but he was less effective than Fernandinho in terms of tactical fouls and emergency tackles. That gave opponents a few more fast-break opportunities.

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Then, their opponents made the most of those chances by charging in on a disheveled set of defenders. Star CB Aymeric Laporte was hurt for much of the season and never really reached fifth gear, which meant that Fernandinho went from backup to minutes-leader. Voila: quality shots.

With Fernandinho now 35, and with John Stones and Benjamin Mendy struggling to fully retain Pep Guardiola's trust, a remodel has begun. A healthy Laporte could solve one problem, but City have acquired 25-year-old Nathan Ake from relegated AFC Bournemouth and might not be done. How this duo shakes out will determine a massive portion of the Premier League race, perhaps even more than if City were to acquire Lionel Messi up front.

Manchester United goalkeepers

We don't completely know what United have in store for the remainder of this transfer window, but theoretically they don't have to make any major move. The Red Devils were the Premier League's points leaders after acquiring Bruno Fernandes in late-January, and while both attack and defense have room for upgrades, there were no definitive weaknesses.

Adding 23-year-old midfielder Donny van de Beek from Ajax gives United an upgrade in creativity in the middle, but as things currently stand, the most interesting position battle might come at the back.

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With 23-year-old Dean Henderson returning from loan after two productive years with Sheffield United, Ole Gunnar Solskjaer now must decide between one of the most proven long-term entities in the league (29-year-old David de Gea) and a battle-tested, but not Europe-tested, Henderson.

Goalkeeper stats are obviously context-dependent, but here are some per-90 averages from all competitions in 2019-20:

- de Gea: 10.5 shots against, 1.02 XG conceded from shots on target, 1.02 goals against, 70.1% save percentage
- Henderson: 11.2 shots against, 1.17 XG conceded from shots on target, 0.94 goals against, 74.5% save percentage

Keeper stats can be unreliable. De Gea was unsustainably brilliant in 2017-18, unsustainably bad in 2018-19 and directly in between last year. Henderson, meanwhile, posted better averages last year in the Premier League than the year before in the Championship. That's not quite how that's supposed to work. Do you rely on last year's small-sample success as a sign of years of brilliance to come and cast de Gea aside? Do you stick with the veteran a bit longer?

The Chelsea attack -- like, all of it

As with Manchester City, Chelsea's success could be dependent on a rebuilt defense, but forgive me for getting distracted by bright, shiny objects. Chelsea has also rebuilt its attack ... on top of an already pretty good attack. They added RB Leipzig forward Timo Werner and Ajax winger Hakim Ziyech, and they're almost certainly going to add Bayer Leverkusen attacker Kai Havertz in the coming days. That's in addition to young attackers Tammy Abraham, Christian Pulisic and Callum Hudson-Odoi, as well as the wily veteran Olivier Giroud.

Chelsea will, upon the addition of Havertz, boast seven or eight Premier League-quality attackers for what might amount to either three or four spots in the lineup. How in the hell will this all fit together?

Here's what we broadly know about each player:

- Werner, Abraham and Giroud are all primarily centre forwards. Over the last three years in league play, from the center, Werner has averaged a combined 0.84 XG+XA (expected goals plus expected assists, per Opta), Giroud 0.79 and Abraham 0.70. We'll see how Werner's numbers are impacted by the move to the Premier League.

- Ziyech split time between central midfield and right winger at Ajax; predictably, he was more productive at the latter (1.07 XG+XA, last three years) than the former (0.95), but if clutter becomes an issue, he could move around.

- Pulisic and Hudson-Odoi are primarily wingers. Hudson-Odoi has been used almost completely on the right, while Pulisic has logged lots of minutes on the left and right through the years.

- Havertz could be the wild card, assuming he indeed ends up in the blue shirt. Over the last three years in the Bundesliga, he logged 37% of his minutes from a central attacking midfielder role (0.45 XG+XA), 32% at right winger or right attacking midfield (0.54), 16% in central midfield (0.44) and 8% as a centre forward (0.74). He could be the anchor for lots of different looks.

Lampard has a wealth of options, but we'll see what choices he makes.

La Liga

Real Madrid's midfield

You know the coronavirus stoppage has thrown the sports world for a loop when Real Madrid decides it needs to watch its spending for a bit. Los Blancos haven't really brought anyone new into the fold this offseason, and they might not, but they do have one pool to choose from: loanees. But while players like midfielder Alberto Soro (back from Zaragoza), fullbacks Alvaro Odriozola (Bayern Munich) and Sergio Reguilon (Sevilla), winger Hugo Vallejo (Deportivo) and striker Borja Mayoral (Levante) might all eventually figure into manager Zinedine Zidane's plans to some degree, one particular loanee will officially see his time come at the Estadio Santiago Bernabeu: midfielder Martin Odegaard.

The 21-year old from Norway made his Real Madrid debut at the age of 16, but made just three appearances before getting sent away to soccer boarding school: the Eredivisie's SC Heerenveen for two years and Vitesse for one, followed by a year of finishing school at Real Sociedad, where he logged 40 appearances in all competitions, with seven goals and 10 assists. He joins an already crowded midfield that includes veterans Toni Kroos, Luka Modric and Casemiro, plus 22-year-old up-and-comer Federico Valverde. All four of them logged over 1,900 minutes in league play last year.

His passing stats are more like Casemiro's than anyone's, but with Sociedad he averaged 0.37 XA+XG per 90 minutes, better than anything the Madrid quartet has produced over these last few seasons.

Does Modric give way to the youngster? Does Zidane end up fancying Odegaard more as a winger, as he was used for quite a few of his Eredivisie minutes? His usage could determine whether we have a La Liga race this year, or whether Real runs away with the title.

Barcelona's midfield

Talking about Barcelona at the moment is the ultimate in known-knowns vs. known-unknowns. The latter -- that whole "Leo Messi very much wants out, but the transfer fee is mammoth, even by European soccer standards" thing -- muddies up the waters for talking about anything else. But here's what we do know: Barca did trade Arthur to Juventus for Miralem Pjanic, brought in winger Francisco Trincao from Braga and brought back attacking midfielder Philippe Coutinho from Bayern Munich.

We'll have to wait to figure out Coutinho's and Trincao's roles, because we have to see what happens with Messi first. But let's talk about the Barca midfield.

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Last year it was led by 23-year-old Frenkie de Jong, Arthur (24) and three veterans in Sergio Busquets, Arturo Vidal and Ivan Rakitic. Rakitic is gone, Vidal could be soon and, as mentioned, Arthur was replaced by the 30-year-old Pjanic, who was second on Juve in assists last year.

A starting point of de Jong and Pjanic, with Busquets still playing a large role, is pretty good, but I continue to hold out hope that new manager Ronald Koeman will determine that de Jong could play more of an interesting role moving back to centre-back, where he played for Ajax for much of 2017-18. He has still averaged 0.18 assists per 90 from that position -- by comparison, he averaged 0.08 from central midfield for Barca last year -- and playing there allowed some of his nature-made defensive abilities (ball recoveries, aerials, dispossession) to shine.

If Koeman thinks Pjanic and Busquets can hold down the fort in a 4-2-3-1 (or perhaps youngsters like Carles Alena and Riqui Puig can play larger roles), then he has an opportunity to move de Jong and improve his attack while improving his defense. Either way, Koeman has some decisions to make here.

Bundesliga

Bayern Munich's wings

There could still be a bit of a domino effect of moves regarding the Champions League winners during this transfer window -- if midfielder Thiago ends up leaving for Liverpool, as seems to be his desire, then that might prompt a new acquisition and position battle. But right now, all we know for sure is that Coutinho is heading back to Barcelona and former Manchester City winger Leroy Sane has moved back to Germany.

Sane joins an astounding crew of wingers at the Allianz Arena. Serge Gnabry scored 23 goals in all competitions last year, primarily from the left wing. Kingsley Coman scored eight, including the Champions League clincher. Veteran Ivan Perisic came into his own after Hansi Flick's midseason hire, and the Inter Milan loanee could still end up in Munich this coming year. Thomas Muller can play out wide when he needs to, and Alphonso Davies might have become a world-class winger if he hadn't instead become a world-class fullback last season.

Sane's 2019 injury might have led us to forgetting just how good he is, but during Manchester City's two Premier League title runs in 2017-18 and 2018-19, he posted a combined 20 goals and 25 assists. He's outstanding. If he's in the lineup, some other outstanding winger won't be.

Borussia Dortmund's attacking midfield

Tormeister Erling Haaland will be lining up at the top of whatever formation manager Lucien Favre favors. That much we know. The 20-year-old scored a combined 44 goals for Red Bull Salzburg and Borussia Dortmund last season and returns for a full season at the Signal Iduna.

The row of attackers behind Haaland, however, has minutes up for grabs. You could say that the youth-friendly BVB have made three primary young-talent acquisitions during this window: they signed 17-year-old Jude Bellingham from Birmingham, they brought Real Madrid's 18-year-old Reinier in via a two-year loan, and they evidently managed to keep the marvelous Jadon Sancho for another season as Manchester United have seemingly elected not to meet the asking price.

Bellingham could play just about anywhere, but might mostly roam the midfield for BVB. Sancho does most of his work from the right wing, Thorgan Hazard dished 13 assists in league play from the left wing, veteran and central attacking midfielder Marco Reus is still good for double-digit goals when healthy, 17-year-old American Giovanni Reyna has potential from all of these positions (and has expressed a preference for that CAM spot), and Reinier posted six goals and two assists in 14 matches for Flamengo last year, also from the CAM position.

That's five high-level players -- without even counting Bellingham (who has looked good further up the field) -- for two to three spots on the pitch.

Favre has to figure out a nice way to balance playing time for the club's future stars while giving Bayern another fight, as BVB have done the last two years.

Serie A

Juventus midfielders

Back in July, as Juventus were wrapping up their ninth consecutive Serie A title, I wrote about how this was maybe the club's least convincing win in the title streak and how the Bianconeri were a little bit lucky to both win as many close matches as they did and watch all their primary challengers falter at just the right time. I also noted something that club higher-ups most certainly already new: the roster needed a makeover. Juve was getting old and creaky and needed new energy, especially in the midfield.

The makeover has begun. Blaise Matuidi left for Major League Soccer's Inter Miami, and forward Gonzalo Higuain is likely to follow. Miralem Pjanic left for Barcelona, while the younger Arthur was sent back in return. American Weston McKennie was brought in from Schalke, while a host of players returned from loans, including 20-year-old midfielder Dejan Kulusevski (10 goals and eight assists for Parma, albeit more from a winger role).

Their moves might not be over -- we'll see what happens with 33-year-old Sami Khedira and 29-year-old Aaron Ramsey -- but that's already a solid refresh. Arthur is a solid passer and could thrive in a pivot-type role, McKennie is developing a solid pressure-and-physicality presence, and Kulusevski is already a proven creator. Add them to a stable that still includes 23-year-old Rodrigo Bentancur, 25-year-old Adrien Rabiot and potentially Khedira and Ramsey, and you've got a lot of potential combinations for new manager Andrea Pirlo. But it might take him a bit to figure out the best combo of the bunch.

Napoli forwards

While Inter Milan has added wingback Achraf Hakimi, Atalanta has added attacking midfielder Aleksey Miranchuk and both AC Milan and Roma have made some interesting smaller moves (Lazio, not so much), by far the most interesting move among Juve's main challengers came when Napoli added 21-year-old striker Victor Osimhen.

After scoring 20 goals on loan for Belgian side Charleroi in 2018-19, Osimhen landed at Lille and scored 18 for Lille, including two in the Champions League. Napoli were utterly desperate for firepower up front: Gli Azzurri averaged just 0.101 XG per shot in Serie A last year, second-worst in the league and by far the worst among contenders. Even an average performance in this regard could have resulted in five to 15 more goals, far fewer tight losses and a sustained title contention. So they spent a club-record $70 million for Osimhen, who averaged 0.19 XG per shot in Ligue 1 last year.

Only winger Jose Callejon has left the club, though. Centre-forward Arkadiusz Milik scored 11 league goals and averaged a healthy 0.16 XG/shot himself -- really, veteran Dries Mertens was the biggest offender from an inefficient shots standpoint -- and 29-year-old Lorenzo Insigne remains dangerous on the left wing. Hirving Lozano and super-sub Fernando Llorente could remain solid options, too.

Manager Gennaro Gattuso prefers a 4-3-3 structure, which could lead to a couple of players logging lots of minutes outside of their best positions; will the addition of Osimhen provide the balance that last year's attack lacked, or will it just create a logjam?