...one of the options being considered for replacing kickoffs entails giving the ball to the team that would have been kicking off at its own 30, automatically facing a fourth down and 15 yards to go. The team can then choose to punt or go for it, via fake punt or otherwise.
In other words, the kickoff would be replaced with the punt, and the onside kick would be replaced with a fourth-down conversion...
It is...interesting. I'd honestly make it even further than "4th and 15" though. It needs to be about as unlikely to succeed as regular onside kicks are now. I'd make it "4th and 20" and force them to get past midfield on one try.