We're pretty sure.
The MLB tonight announced that they would be extending their contract with Sony to continue developing new games with the MLB license. While this comes as no surprise, the MLB also announced that the popular MLB The Show series would no longer be a Playstation exclusive, and would be arriving on other consoles as early as 2021. While no official confirmation has been given that upcoming MLB The Show games will arrive on Switch, Nintendo of America did retweet the news from their official Twitter account.
— Nintendo of America (@NintendoAmerica) December 10, 2019