Underscoring once again how unpredictable the online video space is, Twitter has emerged as the unlikely winner of the rights to stream NFL Thursday Night Football (TNF) games for the 2016-2017 season. Just yesterday I wrote that with Facebook and Apple bowing out, the bidding likely came down to Amazon, Verizon and Google, with Verizon the most likely winner for a variety of reasons.

On the one hand, Twitter’s interest in streaming the TNF games makes sense, as recently returned CEO Jack Dorsey has publicly stated that a top 2016 priority is live streaming, including leveraging its Periscope product. The 10 TNF games give Twitter a marquee property to highlight live streaming, which complements Twitter activity around all games. And Twitter already had a deal in place with the NFL for highlight clips.

Defensively, the move also makes sense for Twitter as Facebook has also made live streaming a priority and is itself investing in differentiated content. Facebook Sports Stadium, launched earlier this year, is positioned as a real-time space to engage with friends around live sports events and will no doubt evolve as a bigger threat to Twitter going forward. Meanwhile YouTube is poised to enter live streaming imminently through the release of its YouTube Connect feature.

All of that said, the deal is still a bit of a head-scratcher. Today’s announcement clearly says that Twitter has streaming rights across “mobile phones, tablets, PCs and connected TVs.” But back in 2013, the NFL signed a 4-year deal with Verizon for $1 billion that also gave Verizon rights to stream to phones. I’ve reached out to both the NFL and Twitter for clarification of how the new TNF deal’s rights align with Verizon’s.

This is a critical issue because Twitter itself says that 80% of its usage is now on mobile (same as with Facebook, which is why I thought Verizon’s rights were an impediment to Facebook’s TNF interest). For Twitter, the value of TNF largely comes down to mobile consumption of the game. Any mobile restrictions due to the preexisting Verizon deal that diminish Twitter’s mobile reach make the deal’s payoff more uncertain.

But even assuming unfettered mobile rights, there are still unknowns around users’ interest in consuming a 3-hour plus game on a mobile phone, especially if it’s a blowout. Add to this mobile data caps and expensive plans that inhibit long-form viewing on mobile devices absent WiFi and it’s even murkier how intensively the TNF games will be watched. This is one reason I thought Verizon had an edge - by controlling its own mobile network, it could have carved out game viewing from data usage (as long as the FCC didn’t cry foul).

It’s important to keep in mind that Twitter will actually be the fourth way fans can watch the games, under the NFL’s clever “Tri-Cast” distribution approach with CBS and NBC splitting broadcasts and NFL Network simulcasting. The broadcasters can also stream the game to authenticated users giving them another outlet. So Twitter will be battling for every single viewer who may be drawn to these other options instead. Such is the power of the games that the NFL is able to sell the rights to multiple parties.

Last but not least, according to Twitter, 79% of its user base is international. There’s no doubt the NFL has an international following, but is it substantial enough to draw big numbers?

So bottom line, there are many variables for Twitter in the TNF deal. Ultimately, can the games help expand Twitter’s user base, which is the key knock on the company, or will it mainly draw existing users? Will TNF substantially expand Twitter activity around the games beyond what was already occurring? And can Twitter monetize the games to generate an ROI?  (this was ultimately Yahoo’s Achilles Heel).

Despite all of the questions, I still give Twitter credit for taking a big swing with TNF and trying to innovate with marquee live content. How it ultimately pays off is unknown, but the deal once again reflects how dynamic the online video, TV and sports industries are currently.