Maybe he thought that if he put a GK as an MC and a striker as GK, he would score more points for the mini-competition.
Seriously, this game is just nonsense at times. This is not new as such as during the second period that I played this game (a lot of seasons ago), a weaker team scored 2 goals past my team despite it having a GK as MC.
Things just happen in this game to satisfy the calculated outcomes of the game engine or to satisfy what it wants, even if that means to go against football logic and even logic itself. But sometimes, I have the impression that there are faults and errors that occur in this game.