To solve this, I think a 'Percentage-of-completion'-method should be introduced to calculate the players' number of clean sheets. In short, this means the amount of clean sheets is determined by how long the goalkeeper manages to keep a clean sheet. A standard league match is 14 minutes, so if a player keeps a clean sheet for 7 minutes, he will get a +0,5 clean sheets added to the statistics. If a player keeps a clean sheet for 8 minutes, he will get 8 / 14 = +0,57 clean sheets added to the statistics, etcetera. This method of tracking statistics gives a better representation of the relative clean sheets that have been obtained.
I understand implementing a system like this might bring some issues with it (like more work to update the statistics/problems with past statistics/...). Another option is to just give +0,5 clean sheets to those who kept a clean sheet for one half, however I prefer my suggestion.
And of course if you have another suggestion, please post it here
