Football Statistic Match Ratings (Average for Past 3 Games)

[SWRevolution]

I'm building out a database of Football statistics for the Football Teams I support, however an issue I have is that it is all automated, except for the average rating for the past three matches (Recent Form). At the moment I have to manually select the cells that would contribute to this statistic. I know how to average the last three cells of a range, however depending on where the player plays and the formation that is used, their name can end up in a different column match-on-match. Here's an example (For the sake of this example the cell with "Starting XI 1" is cell E2. Column A is the player names and Column B is the Number of Games Played and Column C is Recent Form. In Cell C2 (For "Lucas" the Formula I have is "=IFERROR(SUM(AD3, S4, AB5)/IF(B2<3, B2, 3),6)"

[TABLE="class: grid, width: 500"]
<tbody>[TR]
[TD]Starting XI 1
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 2
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 3
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 4
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 5
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 6
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 7
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 8
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 9
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 10
[/TD]
[TD]Rating
[/TD]
[TD]Starting XI 11
[/TD]
[TD]Rating
[/TD]
[TD]Sub 1
[/TD]
[TD]Rating
[/TD]
[TD]Sub 2
[/TD]
[TD]Rating
[/TD]
[TD]Sub 3
[/TD]
[TD]Rating
[/TD]
[/TR]
[TR]
[TD]Lloris
[/TD]
[TD]5.4
[/TD]
[TD]Trippier
[/TD]
[TD]6.6
[/TD]
[TD]Sánchez
[/TD]
[TD]6.6
[/TD]
[TD]Vertonghen
[/TD]
[TD]7.3
[/TD]
[TD]Davies
[/TD]
[TD]6.9
[/TD]
[TD]Dembélé
[/TD]
[TD]7.1
[/TD]
[TD]Dier
[/TD]
[TD]7.1
[/TD]
[TD]Lamela
[/TD]
[TD]6.4
[/TD]
[TD]Eriksen
[/TD]
[TD]7.6
[/TD]
[TD]Dele
[/TD]
[TD]6.6
[/TD]
[TD]Kane
[/TD]
[TD]6.9
[/TD]
[TD]Son
[/TD]
[TD]6.2
[/TD]
[TD]Lucas
[/TD]
[TD]7.3
[/TD]
[TD]Sissoko
[/TD]
[TD]6.5
[/TD]
[/TR]
[TR]
[TD]Lloris
[/TD]
[TD]7.2
[/TD]
[TD]Aurier
[/TD]
[TD]6.5
[/TD]
[TD]Alderweireld
[/TD]
[TD]7
[/TD]
[TD]Vertonghen
[/TD]
[TD]6.8
[/TD]
[TD]Davies
[/TD]
[TD]6.7
[/TD]
[TD]Sissoko
[/TD]
[TD]6.5
[/TD]
[TD]Wanyama
[/TD]
[TD]6.6
[/TD]
[TD]Lucas
[/TD]
[TD]6.7
[/TD]
[TD]Eriksen
[/TD]
[TD]6.4
[/TD]
[TD]Son
[/TD]
[TD]7
[/TD]
[TD]Kane
[/TD]
[TD]8
[/TD]
[TD]Dembélé
[/TD]
[TD]6.7
[/TD]
[TD]Lamela
[/TD]
[TD]6.4
[/TD]
[TD]Llorente
[/TD]
[TD]6.6
[/TD]
[/TR]
[TR]
[TD]Vorm
[/TD]
[TD]6.4
[/TD]
[TD]Trippier
[/TD]
[TD]6.5
[/TD]
[TD]Sánchez
[/TD]
[TD]6.6
[/TD]
[TD]Vertonghen
[/TD]
[TD]7.6
[/TD]
[TD]Davies
[/TD]
[TD]5.8
[/TD]
[TD]Dier
[/TD]
[TD]7.5
[/TD]
[TD]Dembélé
[/TD]
[TD]6.5
[/TD]
[TD]Eriksen[/TD]
[TD]7.8
[/TD]
[TD]Dele
[/TD]
[TD]7.7
[/TD]
[TD]Son
[/TD]
[TD]6.6
[/TD]
[TD]Kane
[/TD]
[TD]7.1
[/TD]
[TD]Lucas
[/TD]
[TD]6.8
[/TD]
[TD]Wanyama
[/TD]
[TD]6.7
[/TD]
[TD]Lamela
[/TD]
[TD]6.9
[/TD]
[/TR]
</tbody>[/TABLE]

Any help would be much appreciated!