It was announced earlier this week that users can now rent and stream movies on Facebook , and today it’s already possible to watch a free live baseball game on the social networking site.

According to a source, Major League Baseball (MLB) is experimenting with video stream content on Facebook. Baseball fans can now watch a spring training game live on MLB’s Facebook Page for free. One game will be broadcast live on the social network each day through the end of spring training in April, including the regular season.

MLB is experimenting on free games to drive new subscribers to MLB.TV, which lets users watch regular season games and select spring training games online or on a mobile device for $20 and $25 a month, and $120 for a full season-long subscription to MLB.TV’s digital video package. The games are free, but you can’t expand the video beyond the small box in the Facebook News Feed. This free video stream promotion is supposed to test Facebook’s promotional power.

Bob Bowman, CEO of MLB.com, pro baseball’s digital operation in an interview said, “What we’re trying to do is figure out who these fans are, whether they like it, and whether they share it.”

A live sports game broadcast has a bigger potential on Facebook because users are more likely to share a live event and engage with real-time status update.