When Spurs signed him in January of 2015, Dele Alli was compared by several commentators to a young Steven Gerrard. These observers claimed that he had the same industry, eye for goal, and passing ability that defined Liverpool's former captain. When Spurs kicked off the season in early August against Manchester United, Alli, to the surprise of many, showed that the comparisons weren't that far fetched as he featured in midfield alongside Eric Dier.

But while Dier has become an anchor in midfield, Alli's role in this side has been far more fluid. These days it's possible that the Gerrard comparison is actually too limiting as a description of Alli's long-term potential. In only one season of Premier League football the English phenom has played in midfield, in the attacking three of Mauricio Pochettino's 4-2-3-1, and even at times as a false nine in a de facto 4-3-3.

As we move toward the end of his first full season in England's top flight, it's worth asking: What does the future hold for Dele Alli? Is he a ludicrously talented box-to-box midfielder whose best role is something along the lines of Gerrard's old role at Liverpool or perhaps, thinking more ambitiously, Paul Pogba's role in Juventus's midfield? Or is he an attacking midfielder who can play anywhere across the front three, provides a good vertical threat, and often looks to play that final killer ball? Or, to be even more daring, does his future lie in a more structured attacking role as a second striker or false nine?

To answer the question, we'll need to briefly review his performances in each role this season.

Dele Alli in the Midfield Two: Week 1 - Week 12

For roughly the first third of the season, Dele Alli played alongside Dier in the midfield pivot. This was often described as a 4-2-3-1 but even at this early stage the actual style was more complex. From the first match of the season, Spurs have often used Dier and Toby Alderweireld in a way perhaps best compared to Dortmund's use of Julian Weigl and Mats Hummels. Dier is the mdifield water carrier who plays short, simple passes, and looks to break up attacks before they get into Tottenham's defensive third (or at least to delay them enough to allow the defense to get set).

Alderweireld, meanwhile, sits deep when Spurs are defending (and often covers for his more defensively adventurous partner Jan Vertonghen) but then routinely gets forward when Tottenham are in possession and looks to play long vertical balls to spring attacks. His assist on Alli's goal against Everton is an example of this:

Alli got most the credit for the finish (understandably) but the goal only happens because of Alderweireld's stunning pass. And he has been making these sorts of passes all season long.

Practically speaking this means that Dier has routinely dropped off and partnered Vertonghen or Kevin Wimmer while Alderweireld has moved forward to almost be a deep-lying playmaker setting up Tottenham attacks.

Given Dier's mixed responsibilities that demand he stay deeper, Alli was often left as the only pure midfielder in the midfield two. This meant he had significant defensive responsibilities in midfield, particularly to work in sync with the attacking three as they pressed or dropped off the ball. (In other words, he needed to do what Ryan Mason never learned to do over a full season in the role.)

Here is a StatsZone chart showing Alli's defensive activity from his time in this role. This particular chart comes from one of his finest games during this run, the 1-0 victory against Crystal Palace in September. In this game, Alli partnered Dier in midfield behind an attacking trio of Erik Lamela, Heung-Min Son, and Nacer Chadli. Here's what Alli did defensively:

(The Xs indicate tackles, the circles are clearances, and the diamonds are interceptions.)

As you can tell, Alli still played fairly deep at this time and he did it extremely well. Partnered with Dier, Spurs had a strong midfield duo that executed Pochettino's system at a level that the Masontaleb midfield of last season never even approached. But then the November fixture against West Ham arrived and Pochettino suddenly found a new use for his young midfield star.

Attacking Midfielder: Week 13 - Week 17

For several games after the West Ham throttling, Pochettino used Alli in a free role that allowed him to drift anywhere across the attacking third in Pochettino's 4-2-3-1 shape. This move did several things for Spurs. First, it gave the team a more central vertical threat that had been missing when Pochettino had Mousa Dembele or Chadli partnering the other normal members of the front three, Lamela and Christian Eriksen. All four of those players are more lateral drifters. Alli added vertical runs as well as a surprisingly strong vertical passing game. In fact, it only took 22 minutes for Alli to get his first assist on a Harry Kane goal after playing a short slipped-in through ball that was lucky to reach Kane before the English striker lashed it home:

The above goal also does a good job of showing how Spurs were playing at this point: The overall shape is still Pochettino's basic 4-2-3-1: Alli is in the number 10 role, Kane is in front of him, and Eriksen is to his left. That said, Pochettino tinkered with this basic personnel grouping a bit more which means there is still another role for Alli we need to consider.

Support Striker / False 9: Week 18 - Present

Beginning with the Norwich game we saw some additional tweaks to the formation made by Pochettino. There are three basic pieces to the modification:

First, Harry Kane was asked to drift into wider areas when Spurs were in transition. This meant that he was now making outside-in runs even more regularly than before. (That said, using strikers in this way has been a distinctive of Pochettino's ever since his arrival in England.)

Second, Christian Eriksen was asked to drop deep to receive the ball and to provide some support to Dembele in midfield. This not only gave Spurs more numbers in midfield, it also meant that Eriksen's exemplary passing ability was now going to be showcased even more often as the Danish playmaker would be receiving the ball more regularly and in deeper roles where he'd have more time and space on the ball. This move also made sense when you remember that Eriksen is a graduate of the Ajax academy and that he always played in a midfield trio during his time at the Dutch club.

Finally, and this is the most daring shift Pochettino made, Dele Alli was asked to play as a sort of false nine just ahead of the midfielders and between Kane and Lamela or Son. In one sense, this seems crazy. You're really going to ask a 19-year-old midfielder in his first Premier League season to play as a false nine in a hybrid 4-2-3-1/4-3-3 system?

But that understates Alli's quality and misses the most important part about the move: This shift brings out Alli's best qualities. In this system, Spurs are playing a 4-3-3 when out of possession or in transition and a more conventional 4-2-3-1 (with Alli behind Kane) when in sustained possession in the attacking third. So the only time Alli played as a false nine is when the opposition was ready for a counter-attack, which plays naturally into Alli's hands as an aggressive vertical runner. The other key here is that the most important type of pass for a false nine in a counter attacking system to make is that delicate through ball that splits center back and fullback and that the wide attacker latches onto via a run around the fullback and into the channel. And, if we've learned anything this year about Alli, it's that he is a master at making that sort of pass. In fact, of the 10 assists Alli has had this season, eight have come since the Boxing Day fixture against Norwich where we saw him used in the false nine role for the first time. His assist to Kane in that game is representative of how he has worked in this role:

Which role is best for Alli?

This single question is actually probably two separate questions: The first is what role is best for Alli's development as an overall player who will also thrive for England and wherever he goes next after Spurs? The second is what role is best for Alli at Spurs in the quixotic system of Mauricio Pochettino?

The answer to the first question is probably "midfield." Alli has the defensive ability and energy to work as a box-to-box player, but his eye for goal, passing ability, and technical ability make him far more than a typical box-to-box midfielder. In this role, he could star in a 4-2-3-1 system, 4-3-3 system, or even in the modified 4-4-2 approach as a wide creator that is now popular at some clubs. To put it bluntly, in midfield his ceiling is probably somewhere between Ilkay Gundogan and Paul Pogba—which is crazy, but also not an unreasonable idea given how impressive he has been at age 19. Playing in midfield will allow Alli to develop as an all-around player who can work in multiple roles and systems.

That said, the answer to the second question is more complex. The chief problem Spurs need to address this summer is in midfield. Currently the team is heavily dependent on Eric Dier and Mousa Dembele to fill the vital defensive midfield role at the base of Pochettino's attacking system. When Dier is out, Dembele is really the only player Spurs have who can step into that role. But this raises multiple problems for the squad:

First, when Dembele is playing in that number five role, who plays the more box-to-box midfield role?

Second, Dembele is in his late 20s and has a history of muscle injuries. There's no way Spurs can reasonably count on him next season to start as the box-to-box player in Pochettino's system and back-up Dier as the number five in case of injury. Assuming the team makes the Champions League, they will be playing at least 45-50 fixtures next season and that's likely a very low number because it assumes a group stage exit and poor performances in both domestic cups. The actual number of fixtures may well approach 60. You cannot expect a player in his late 20s with a history of muscle issues to last an entire season at that pace.

This is where Alli's role becomes a live question: Should Spurs focus on finding a pure defensive midfielder to replace Dier and simply use Alli as the box-to-box player in the system when Dembele isn't available? Or do Spurs need to find a more versatile midfielder who can play both roles in midfield, just as Dembele can? That would allow the team to keep Alli in the attacking three.

A further question is what Spurs might do with their attacking three next season. With up-and-coming youngsters and loanees included, the options Pochettino has for his front three are lengthy: Alli, Eriksen, Lamela, Son, Chadli, Josh Onomah, Clinton N'Jie, and Alex Pritchard. Suppose you decide to shift Alli back into the midfield two, what happens to his central vertical runner role in that front four? Can Onomah or Clinton fill that role? Could Son be shifted into the number 10 role and used in that capacity? Or would the team look to sign a new player there rather than try and find a do-everything midfielder to back up both Dier and Dembele? These are the questions the club will be asking as we approach the summer transfer window and, one hopes, an exciting and busy 2016-17 season.