Last week, you could rent a movie on Facebook. Today, you can watch a live pro baseball game on the site.

Still think Facebook can't be a big player in Web video

You can watch the game--today it was a pre-season matchup between the Dodgers and the Rangers--for free, via Major League Baseball's page.

If you click on the image, you'll be directed off-site, where you can sign up for a (free) account and watch the game on a full screen. And maybe you'll end up liking it so much you'll end spending up to $120 for a season-long subscription to MLB.TV's digital video package.

Which is really the point of this experiment, says Bob Bowman, CEO of MLB.com, pro baseball's digital operation. Bowman says the free games on Facebook, which began yesterday and will run until opening day at the end of month, are merely supposed to test Facebook's promotional power. (The folks behind Ultimate Fighting Championship have been trying the same thing, by showing some of their preliminary matches for free and trying to upsell viewers on a pay-per-view buy offsite.)

It's possible that the league will keep running a single free game a day on Facebook during the regular season, too. MLB.com has tried that in the past on mobile phones, and will be doing it on its own Web site this year as well.

But Bowman says there aren't plans to give MLB.TV subscribers full access to games via Facebook, and doesn't plan on selling individual games on the site, either.

"What we're trying to do is figure out who these fans are, whether they like it, and whether they share it," he says.

So in case you were planning on panic-selling some shares tomorrow: This move doesn't threaten any established distribution business any more than Facebook's one-off movie rental threatens Netflix. For now.

Still, just because Bowman and company are starting with a toe-touch doesn't mean they couldn't take a deeper plunge later on. And live sports seems like something that lends itself quite nicely to Facebook's platform--much more so, really, than watching movies like "The Dark Knight."

And unlike the "The Dark Knight" experiment, there's no e-commerce angle here for Facebook. Users don't need to use Facebook Credits to watch the game, and if MLB.com generates some subscriptions, Facebook won't get a lead-gen fee.

But again, it's easy to imagine ways that Facebook could participate in this if they wanted to elbow their way in.

For now, though, the site seems content to let developers like Warner Bros., and MLB.com experiment with interesting ways to deliver video--and potentially, all sorts of entertainment--via their platform. Smart. And worth watching.

Story Copyright (c) 2010 AllThingsD. All rights reserved.