When determining the value of a defender, one area that often gets overlooked is the required structure of an Fantasy Premier League squad.  Since we must carry five defenders, we have to account for the cost of our bench players as well as our starters in determining what the true cost or value is for any player.

Heavy Hitters v Rotation

Many players like to go for one, two, or even three big hitter defenders when structuring their teams, something like this in terms of price.

5.5/5.5/5.0/4.5/4.5 = 25

I’m going to take a different approach to see where the value points might be, by considering the sunk costs associated with our back lines.  And I will be arguing that a four or five way rotation of cheaper defenders might actually be the more cost effective strategy, something alone the lines of

4.5/4.5/4.5/4.5/4.5 = 22.5

If you have to spend the money on the bench spot, why not make that money work for you in a rotation?

Here Comes The Science

Firstly, I’m going to look at 4 points per game (PPG) as an excellent score for a defender, one which many would pay a premium for.  Last season, only four defenders amassed the 152 overall points this rate would have gotten them if they had played every match of the season — 4×38 games: Hector Bellerin, Toby Alderweireld, Laurent Koscielny, Nacho Monreal.

Their prices of 6.0-6.5 underscore their strong seasons and potential.  Additionally, just 21 defenders were able to hit that 4 PPG in 2015-16 regardless of games played, so it seems to be a high barrier.

Members can also look at the Rate My Team projections to see how many defenders are estimated at 24 PPG for the first six weeks.  It won’t take long.

As stated above, the requirements mandate carrying two extra defenders if playing a 352 or 343 formation, so all of us head into our decision making process for the three spots we will use actively each week having already spent money (I will use 9.0m as the baseline cost of the final two bench spots though some might go under that at 8.5  – 8.0 seems especially rash – and a few might power up for luxury rotation and go for 9.5.

So we now have to factor the cost of carrying the two bench players into our assessment of cost so the question of Alderweireld  v George Friend doesn’t become just a question of 6.5m vs 4.5m, but rather –

A) 9.5 (6.5 + the 3.0m shared cost/starter across the backline) vs 7.5 (4.5 + 3.0m) if Alderweireld and Burnley’s 4.5m priced Ben Mee are being played as individuals not part of a rotation; or

B) 11.0 (6.5 + 4.5 bench fodder) vs 9.0 (4.5 + 4.5 in a rotation) if deciding on a second or third premium in isolation; or

C) the aforementioned 25m vs 22.5m total for the defenses of 3 every week starters vs a 4-5 man rotation.

What are we getting for our money?  First, the optimistic Alderweireld and the Premiums scenarios (we will give Alderweireld a score of 4.6 — elite output for a defender — and his lesser Premiums a score of 4.0 each):

A) Three premium defenders total value: 4.2 PPG / 9.5m = .44 PPG/m

B) The value of a lesser second or third individual premium defender in isolation: 4.0 PPG / 11m = .36 PPG/m

C) The total value of the five defenders: 12.6 Points / 25M = .50 PPG/m

Now, the calculation of the cheaper defender rotations.  These numbers are estimates and may very well be too rosy, but they are hopefully somewhat reasonable.

A) No rotation to speak of beyond substantial fixture difficulty changes at intermittent times during the season — a 4.5 defender should be able to garner something like a 20-25% chance of a CS, so over the course of six weeks that would give us about 3PPG assuming a 6 for a CS and a 2 for a starting appearance.  This is not factoring in Bonus, attacking returns, and other scores, so I think it is fairly conservative.

3 PPG / 7.5m = .40 PPG/m

***Comparing to a Premium, it is close — the additional funds seem to garner an additional 10% increase.***

B) In this scenario, we consider that having a four way rotation should give you access to 2 strong CS opportunities/week (at about 40-50% odds), so we hope to be able to yield one CS/week.  We could conservatively consider that a score for our three defenders that week would be at least a 6/2/2 for 3.33 PPG.

3.33 PPG / 9.0m = .37 PPG/m

***Comparing to a lesser Premium, it doesn’t make sense to spend — the additional funds garner a decrease of a few percent.

C) In this scenario, we would rotate five inexpensive defenders, with a goal of securing maybe 9 CS over a six week period, or 1.5 CS/week for three defenders.  We could then consider a score for them to average us 6/4/2 for 4 PPG.

12 Points / 22.5m = .53 PPG/m

*** Comparing to the conventional backline, spending once again does not garner an increased rate of points per game, with another slight decrease here.

Conclusion

So why, then, do we spend money on a premium defender?  Attacking returns, breakout potential, changed circumstances, and out of position status all factor in, but the most plausible argument is likely the lack of risk in paying for coverage of an elite defence.  All of the above speculation is predicated on two very different management set-ups: Alderweireld and the Premiums play themselves — just plug them in and let their potential manifest itself over the long run.  The pay out will hopefully be 24-25 points every six weeks as long as the elite defences do their part. Last year, several did just that from the outset, while others greatly disappointed.  The cheaper defender rotation strategy relies heavily on the odds going as well as they can for a manager, with much more chance of an upsetting result for our paltry investment.  A nightmare scenario of 10 points in six weeks beckons if fortune doesn’t favor us.