Thread:Vrokorta/@comment-28510457-20191010160634/@comment-30408599-20191023131428

https://www.sciencefocus.com/science/the-thought-experiment-how-fast-would-i-have-to-run-to-catch-fire/

Scroll down to "Wrap Up Warm". There it says, to catch clothing on fire, you need to be moving at Mach 2.02. That sounds like a decent estimate for your baseball. This feat is also consistent with Toad in Mario Strikers Charged, who can kick soccer balls hard enough to ignite them, so you don't have to worry about Mario's pyrokinesis invalidating the feat.