This would be something written into their contract, I'm sure some players already have this.
I know the club wanted to change the way they pay players operating more on a 'play better, earn more' policy. Although it would be much hard to entice players to join a club that only plays you if you perform well compared to just getting paid the same wage every week even if you play :censored:.
A goal bonus is not the best idea, but paying players if they perform better is. However, realistically it would take the whole football league to make this happen and not just one team.