Relegated teams squad renewal and performance

Posted on December 3rd, 2018   

What happens to teams when they get relegated? How much do their squads end up changing as a result of relegation, and how does it impact on-pitch performance?

We have performed some analysis on the last five completed PL and Championship seasons (i.e. 13/14 to 17/18) to try to answer these questions.

We first investigate the minutes played by players that start in a team’s squad, and look at how those minutes change in the following seasons – but only minutes at the same team are counted. We do this to get at how changes in squads practically affect the actual players fielded.  Specifically we measure the overlap in minutes played across the team from the starting season.  If a team uses the exact same mixture of players in its matches we would observe a 100% similarity/overlap, whereas if a team has replaced all its players we would see a 0% similarity/overlap. The chart below shows the monthly evolution of these overlaps, averaged for teams that remained in the PL, teams that were promoted to the PL, teams that were relegated to the Championship and teams that were already in the second tier league.

We see that relegated teams, more than the other categories, tend to use on average only about 40% of the previous season’s squad in the new season. Teams participating in the PL tend to have a more similar set of players, starting at around 60% and declining with time.  This is not a surprising observation. Relegated teams face a financial challenge, with considerably reduced revenues despite parachute payments.  At the same time, many players will not want to compete in the Championship after being in the PL. What is interesting here is the difference between the PL and Championship for teams that were already there.  Teams in the PL have more stability in their fielded players.

The graph above shows us that PL teams lose more players when they get relegated. But are the players they lose key first team players or mainly reserve players? To find out, we can look at the minutes played (as a proportion of possible minutes played) over the course of the season by players who eventually leave at the end of the season. To get a good understanding of what’s happening, we can do the same for players that end up leaving the subsequent season too.


This graph reveals that not only do teams that get relegated from the PL lose more players than if they stayed in the PL or teams already in the Championship, but it also shows that the players that leave tend to be key first team players that played a fair amount of the season. These changes come as a result of an average 10 new players for the relegated teams, versus 11 for teams already in the Championship.  For both sets of teams, the percentage of new players coming from a team that participated in the previous season’s Championship is similar, at around 25%.

We now turn to review the net spending of relegated teams, compared to teams already in the Championship. On average the relegated teams have bought around £23M worth of players in the season after relegation compared to only £7M by teams already in the second tier league. On being relegated, not surprisingly, relegated teams sold on average about £29M worth of players, which makes a negative average net spending of -£6M. Regarding net spending of the existing Championship teams, the average was around zero, i.e. they were spending as much buying as they were getting from selling players. This highlights the degree of the financial challenge relegated PL teams face.

Turning now to performance: Relegated teams have a 1 in 3 chance of being promoted straight back into the PL. According to our league table simulations this proportion was expected to be 27%, so the newly relegated teams seem to slightly over-perform in that sense. If we instead compare their finishing position in that first season to what we’d expect of them, then they actually under-perform: the average relegated team’s expected position in their first Championship season was 6th, the observed was only 9th. This is an interesting apparent contradiction.  It suggests that while many teams do well, others do very badly – thereby dragging the average league position down.

In terms of team strength, according to our team strength model, the overall strength of newly relegated teams tends to decline after a season by an average of 4.3%, compared to the teams’ strengths at the time of relegation.  This is a relatively modest change against the backdrop of such large changes in playing staff.  It should be noted however that for a team to be relegated in the first place their strength cannot have been especially impressive to start with.

In general we think the main message of the above analysis is that there seems to be an indisputable decline in strength after relegation to the Championship for a typical team. But at the same time there is a larger than expected number of teams that make it straight back to the PL and the actual team strength decline does not appear to be especially severe.  For the team itself the question of interest is whether they will be one of the third that makes it straight back and, if not, will they be one of the teams that drags down the average?

We attempted to answer this question by looking for correlations between the relegated teams and their subsequent performance.  We found that teams with higher spends managed to temper the team strength decline the most.  So, money does help.  We also found that teams that are able to keep more of their playing staff tend to finish in higher positions.  These findings are of course related.  The message is that keeping your squad as close to intact as possible is what the evidence suggests is the best move.