The Butterfly Effect — which is, loosely, when minor changes to the initial conditions of a complex system can result in radically different outcomes — was most prominently researched in relation to weather models in the 1960s.

But it can, perhaps, also be applied to football teams — and Victor Lindelof.

Did you notice that the Swedish centre-back is a midfielder now, which is working out quite well? And while this is an interesting development in its own right (and much more on this later), it also tells us something about what it means for the systems used in the game.

Let’s take Aston Villa, whose central midfielders play an important role in their build-up. Operating at the tip of the deep triangles that Unai Emery sets up on either side of the goalkeeper, their task is to help regulate the progression of the ball from Villa’s own third into their opponent’s half.

There are two different ways this occurs, generally governed by the way the opposition chooses to approach Villa’s build-up. If they opt to put the Villa players under pressure in this deeper build-up phase, then these triangles act almost like mini rondos, where the players are able to retain possession despite the opposition’s pressing and then look to find escapes into the space behind this pressure.

Given the fact that it’s quite risky to invite pressure like this close to your own goal, Unai Emery’s system provides the players with many escapes. These are either vertical or horizontal. When it comes to vertical escapes, if the Villa players can work their way around an opponent’s press, then they may look to play the ball into the feet of players dropping deeper, who will then allow a tempo shift to generate a quick attack through the centre of the pitch.

If this isn’t possible, a more direct vertical escape might be preferable, especially if the player on the ball is under pressure. In this instance, a ball played into the channel for the striker or one of the forwards to run on to will get them out of trouble and also present a potential route to goal.

The other option available when the opposition pressure is too great is to take the horizontal escape. By feeding the ball across the pitch — often using the goalkeeper who should generally be free — to the other deep triangle, Villa should be able to reset and attempt to construct a different escape route.

The role of the central midfielders in this process is key. Not only do they need to possess the requisite level of technical ability to receive the ball in small spaces with their back to the opposition goal under opposition pressure, but they also need to be able to move the ball on quickly with as few touches as possible.

In the games against Nottingham Forest and Burnley, where he has been used in this role, Lindelof has been up to this task. Of course, as a more traditional centre-back, he doesn’t possess perhaps the same level of technicality as a more traditional midfielder.

On the one hand, this is forgivable: he’s been deployed in the role because of injury to Amadou Onana and Boubacar Kamara, with Douglas Luiz and Lamare Bogarde out of favour or form. But on the other hand, it’s worth noting that, to return to our butterfly-effect metaphor, a seemingly inconsequential tweak to one part of Villa’s system can produce other effects elsewhere.

One of these areas shows up in those moments where opponents choose not to press as aggressively against Villa. Rather than using the deep build-up phase as a chance to bait an opponent and then play through them into the space behind, the Villa players will often use their wide triangles to force the opponent deeper until they have settled possession around the halfway line.

In these moments, we’ve been seeing Lindelof drop out of midfield to the right side of the Villa centre-backs.

This allows Villa’s full-backs to push up higher than they might if there were only two centre-backs guarding the space behind them. With Lindelof in midfield, Matty Cash, the Villa right-back would stay alongside the centre-backs, with the left-back free to roam forward. But with Lindelof dropping, the full-backs can offer width on both sides.

On top of this, the movement of the various players — Lindelof dropping deeper, Cash pushing on, the nominal wide forward coming inside to help overload the middle — can cause a destabilisation of the opposition’s defensive structure, which can lead to space to exploit.

Sharp-eyed Villa fans might be clamouring to remind me that this isn’t a novel tactical setup. Emery has used this approach before, using Kamara as the third centre-back out of midfield.

Here’s a sequence from Villa’s home game against Leicester City last season, where Kamara starts out in a midfield position with Villa in settled possession around the halfway line.

As the play progresses, Kamara drops out of the middle, a movement which prompts Cash to jump forward in the wide area.

With Kamara now on the ball, he sits in the outside centre-back slot on the right, looking for a passing option into the middle.

And because of the space that has opened out with Kamara moving deeper, Youri Tielemans can receive the ball, all as a result of Villa’s rotation.

But despite the lack of structural novelty, there is a big difference between using a more traditional centre-back in this role than a traditional midfielder.

There will be downsides, of course. You would expect a midfielder to play the in-possession side of the role slightly cleaner and with more variation, although Lindelof has shown himself adequate in this against Forest and Burnley.

But there are upsides too. A centre-back playing as a midfielder and dropping into the backline means a team pushing their full-backs higher should feel more secure. And, in deeper defensive moments, when Villa sink into box-defending mode, the addition of an extra defender alongside their nominal centre-back pairing will add a level of aerial cover for opposition boxes.

Equally, dropping in to defend the ‘seam’ between the full-back and centre-back, the additional centre-back from midfield means Villa’s other nominal defenders can retain a good position in the box.

Here’s an example of that from the second leg of the Europa League semi-final against Forest. James McAtee makes a seam run, which is tracked by Lindelof and Ezri Konsa, before playing the ball out wide to Neco Williams in the left channel.

Notice how, in the second image here, Lindelof is able to track McAtee, while Konsa and Pau Torres take up a defensive position in the box, anticipating a cross. When the cross comes in, Lindelof is well-positioned to intercept it.

One final upside that Lindelof offers: the ability to play as an aerial presence in front of a back four against teams who look to go long and hit their striker.

This is what Forest tried to do at times in their Europa League semi-final, given the return of Chris Wood. In this sequence, we can see Villa setting up to press high against a Forest goal kick.

Now, Villa generally set up in a 4-4-2 shape out of possession, but with this higher pressing shape, they’re actually in more of a 4-4-2 diamond structure, with Tielemans ahead of Lindelof helping with the press. You can see that as the camera pans back around once Stefan Ortega, the Forest goalkeeper, has kicked it long.

Although by this point, Tielemans has retreated a little to help out, we can see Lindelof adopting a more zonal position ahead of his backline, ready to deal with the long ball should it arrive.

This means that, when Chris Wood drops off the Villa backline to challenge for the ball, he’s battling with a centre-back, not a central midfielder.

Of course, many central midfielders are good aerially, but in this instance, coming up against a natural centre-back means Wood comes off much worse and Villa end up with the ball.

Perhaps it’s a bit of a stretch to suggest Emery’s small change to his regular team is what has led the charge to the Europa League final — that this is the gentle flap of a butterfly’s wings in one part of the world that helps set off a tornado in another.

But by playing Lindelof as a midfielder, the overall effect on the Spaniard’s system might just create the conditions in Istanbul for Villa to lift a first trophy in 30 years.