I count 5 not from the US, but 2 of which played in predominately US league, yes. Not their fault that's where the best competition in the world is though...
Messi, Beckham, Marta, Vinay Singh, Greg Norman, Nadal, Sharapova, Nowitzki, Jonah Lomu, just to name a few. There are a lot of them in many different sports.
I'm American, so this is just a guess, but Babe Ruth seems to me to be such an icon that even people from other countries and with no interest in baseball would know him. His name constantly comes up in movies, songs, TV shows, and history generally. His impact is beyond just "sports guy." I have no interest in sports not popular in the US, but I know Lewis Hamilton, Michael Schumacher, Don Bradman, Pele, Messi, Maradona, etc. because they are so famous that their names creep into other conversations. Seems like Ruth is in the same category. But, as I said, I couldn't really say because I knew his name by the time I was three years old.
As an American, this was pretty easy even without knowing much about sports. I only recognized half of them, but was able to get the rest by guessing the only people I'd heard of in hockey, football, etc.
• 8 local sports people from domestic US leagues
• 5 international sports people from the US
• Only 3 from the entire rest of the world
No way can anyone be expected to know who Aaron Rodgers or Babe Ruth are outside America lol