The Best Bang For Your Buck Goalkeepers

Now that the Fantasy Premier League (FPL) prices have been released we have enough information to begin planning our teams in earnest and trying to figure out how to get the most value for our £100m. In this article, I will discuss in detail the value available amongst goalkeepers during the forthcoming Premier League season.

Pricing

In our first look through goalkeeper prices, we can spot a few special situations that may present valuable opportunities:

• Boaz Myhill is priced at just £4.5m and is expected to start for West Brom in their initial 8 or so games.
• Southampton keepers are priced at £5.0m (likely due to Fraser Forster’s injury situation) while their overall defensive quality is more similar to those with £5.5m keepers.
• Four teams have backup keepers costing only £4.0m.

Points Potential

Of course, price is only half of what determines value. The other half is the points that we can expect to receive from each choice of goalkeepers.

We can estimate points for a goalkeeper to reasonable accuracy* if we know the number of clean sheets and the number of saves he will accumulate. Fantasy Football Scout members can get estimates of clean sheets from the information in the Season Ticker. For saves, we could use last year’s number; however, the season-to-season correlation of save percentage for a goalkeeper is only about 30%. Hence, the best choice is to estimate saves to be 70% (the league average) plus one third of that keeper’s difference from average last season.

Using this approach, we can estimate the points to be scored by every goalkeeper in every match and by every potential rotation pair. Focusing on the matches in the first half of the season, here are the best strategies available at each price point:

• At £10.0m, Chelsea’s Thibaut Courtois and Leicester’s Kasper Schmeichel give the best value of 0.415 points per pound.
• At £9.5m, Courtois and a £4m keeper give the best value of 0.436 points per pound. If we want a second keeper that actually starts, the best value for this price outlay comes from Southampton’s Marteen Stekelenburg and Aston Villa’s Brad Guzan at 0.424 points per pound.
• At £9.0m, Stekelenburg and a £4m keeper give the best value of 0.446 points per pound. If we want two starters, then the best option is Schmeichel and Newcastle’s Tim Krul at 0.411 points per pound — a substantial drop.
• At £8.5m, Krul and his back up Rob Elliot give the best value of 0.432 points per pound.

We can see that the best option at two price points involves using a £4m keeper as backup. However, it is important to note that, with a non-starting keeper as backup, we will lose about 3-4 FPL points (on average) if our primary keeper does not start. That could occur due to an injury, losing his place to his backup, or simply being rested due to fixture congestion. If we expect this to happen once in the first half of the season, then using two starting keepers gives more value for £9.5m.

At £9.0m, on the other hand, the difference between Stekelenburg and a £4m keeper and the next best option would require Stekelenburg to miss two games to eliminate the advantage. However, if Stekelenburg misses a single game, then the points per pound of that approach, while still noticeably better than other £9.0m strategies, becomes comparable to the value of Krul and Elliot at £8.5m.

Overall, if you feel confident that Stekelenburg or Courtois will start all of the first 19 matches, then pairing them with a £4m pound keeper gives the best value. But If you worry that both may not start all 19 matches, then the best value comes from Krul and Elliot at £8.5m or Stekelenburg and Guzan at £9.5m.

Analysis

First, we can see that all of the £5m keepers other than Stekelenburg offer poor value. It is worth noting that five of the nine keepers who received £5m price tags, based on their results from last season, achieved those results either by having an unsustainably high save percentage or somehow managed nearly as many clean sheets as Chelsea. (Swansea’s Lucasz Fabianski and Costel Pantilimon, in particular, fit this description.) Neither of those feats is likely to be repeated this season.

Second, in each case where a rotation partner is used, there is some advantage to using Myhill instead of another £4.5m keeper. However, the advantage appears to be very small and comes at the cost of having to use a transfer on a keeper around Gameweek 8, so I left those strategies out of the list above.

Finally, cheap keepers in general offer more value than might be expected as the relationship between expected goals conceded and expected goalkeeper Fantasy points is very flat (see graph). The reason for this is that if the clean sheet odds are high then the goalkeeper will gain clean sheet points. If the clean sheet odds are low then the goalkeeper is also expected to make lots of saves, which can help offset the loss of clean sheet points. In other words, there are really no “bad fixtures” for goalkeepers in terms of accruing Fantasy points. It is also worth noting that in 2015/16 FPL has tweaked its Bonus Point System, which is used to allocate bonus points, to give greater weighting to saves. This could mean that goalkeepers could win even more points  against more attacking sides.

•A simple linear model based on save percentage and clean sheets has an R^2 of 0.8, meaning that the predicted scores have a correlation of 90% with the actual points scored.