How come I have only have two impact players in my dynasty?

[utexas]

Week 7 seems to be the change date. Same thing happen to me in week seven.

[moTIGS]

I also had my impact player status go from a receiver to a tailback during the season, which sort of sucked because I could run pretty well anyway (who couldn't in this game?). It'd be nice to have an impact quarterback/receiver combo again, but right now I've got two impact halfbacks on my roster.

I'm not sure how those things get decided, but it doesn't go to your highest overall player. It must be a combo of ratings and performance.