Major League Baseball announced its new rules driven by COVID-19 health and safety requirements. Notably, spitting is banned! I'd imagine that this will be tough to enforce—spitting in baseball is as American as, well, baseball.
Here's the rule:
• Spitting is prohibited (including but not limited to, saliva, sunflower seeds or peanut shells, or tobacco) at all times in Club facilities (including on the field). Chewing gum is permitted.
It's also a good thing the spitball was outlawed in 1920.
That said, the new rules also state that, "Pitchers may carry a small wet rag in their back pocket to be used for moisture in lieu of licking their fingers."