I use Audacity to record the sounds off YouTube. You have to tinker with it some, and audio quality depends on the quality of the audio on the YouTube video.
All-Star games, playoff and World Series games are the best games to grab audio as long as the broadcast televises the intros of the players before the games.
I have a link to my Dropbox folder if anyone is interested. These players are exclusively from the 1970s, '80s and early '90s because that's all I play. But if you're interested in current-day guys, maybe this will give you some inspiration.
One other note: Most of the time, I leave the player's team on the file just because I think it's cool. Obviously, it may seem out of place if the guy has moved on to another team. You can always edit that out, if you like.
https://www.dropbox.com/sh/wuwlo69eh...QMMLpRoja?dl=0