TI #022: Why a role change can completely reshape a player's performance
Timeless Insights #022
What happens when the same player performs differently… simply because his position changes?
At first, the answer seems obvious. Of course a fullback runs more than a centre back, and of course a wide midfielder behaves differently from a central one. Positional differences are one of the most established findings in football analytics.
But that is not the most interesting question.
A more subtle one sits underneath:
How much of a player’s performance actually belongs to the player — and how much belongs to the role he is asked to perform?
I recently talked about a paper exploring this from a player-team perspective:
But how about looking at it from a player-position one?
Because if the same player can produce very different outputs depending on position, then many of the metrics we rely on may be describing the role more than the individual.
That is the core idea behind this study.
Instead of comparing different players across positions, the authors take a much cleaner approach by following the same players and analysing what happens when they switch roles across matches. This removes much of the usual noise in player comparisons and allows us to isolate something more fundamental: how performance changes when only the role changes.
When the same player becomes a different profile
The results are striking, but they become intuitive if you look at them through the lens of role.
Take the shift from centre-back to fullback. The same player suddenly covers more high-intensity distance, sprints more frequently, and becomes more involved in the final third. At the same time, he also loses possession more often, reflecting the increased exposure and risk associated with operating in wider and more advanced areas of the pitch.
None of these changes are surprising on their own. What is more interesting is that they emerge without changing the player, only the role.
This is where the paper adds something important. The differences are not simply explained by physical capacity, but by how that capacity is deployed within a tactical structure. Players appear to operate within the limits imposed by their role, rather than consistently reaching the limits of their physical or technical ability.
In that sense, match performance is not just a reflection of what a player can do, but of what the role requires him to do.
🔒 In the next section, I break down why this has major implications for recruitment, why some projections fail despite “correct” data, and how clubs should think differently about player evaluation when roles are not fixed.
