Is there a solution to Ohtani's walk issue?

Clearly nobody likes the fact that you can just constantly walk the best guy in the sport. It's not good for the sport nor for the fans, nor for the player.

I'm actually not sure what would be a solution to that. If you force the pitcher to pitch they will just throw random pitches, for effectively the same effect.

Is there a major rule change to trigger? Maybe the Nth time you walk him he gets to Nth base? Sounds stupid but it's really not obvious what to do.