'Game of Thrones'
"Game of Thrones" star Clive Mantle lost his ear in a brutal hotel attack. HBO

Since its introduction, HBO GO, HBO’s online content streaming service, has been exlucively reserved as a bonus for cable subscribers to watch their favorite shows online. Now, however, HBO CEO Richard Plepler says that the model could soon evolve into a more open service akin to Netflix.

"Right now we have the right model," Plepler told Reuters on Wednesday at the premier of HBO’s "Game of Thrones." "Maybe HBO GO, with our broadband partners, could evolve."

He added, "We would have to make the math work.”

HBO introduced its HBO GO service in 2010 as a way to let HBO subscribers watch the channel’s programing over the Internet. HBO Go can be accessed through several difference devices, including Apple’s iPhone and iPad, Android devices and Roku boxes, but only by those who already have a cable subscription to HBO GO.

HBO Watch notes that a subscription to the premium cable service can cost between $15 and $20 a month on top of a normal cable bill. If HBO opened up their HBO GO service to non-cable suscribers, customers would expect to pay between $10 and $15 each month for the online-only service, Reuters notes. Under this model, HBO GO would be more expensive than both Netflix and Hulu Plus ($8 per month each).

Currently, the service has 6.5 million registered users, only a fraction of HBO’s total 29 million subscribers. As Netflix and Hulu both begin to roll out their own custom online-only content, it may be a smart idea for HBO to increase their market share by allowing customers to subscribe to an online-only HBO GO.

There’s also another reason that HBO GO may become more than a bonus to cable subscribers: piracy. Currently, HBO’s hit fantasy series “Game of Thrones” is the most pirated television show in the world.

Each episode of “Game of Thrones” was downloaded an average 4.28 million times. To put that in perspective, the season 2 finale “Valar Morghulis” was the most widely watched episode of the series on HBO and drew in 4.2 million viewers when it was aired for the first time.

In short, more people are watching “Game of Thrones” through BitTorrent than legitimate means. And for many fans, there’s simply no affordable way to watch their favorite HBO shows cheaply or legally.

An increasingly large number of television fans (mostly those in their 20s and 30s) have been abandoning the physical box in favor of subscription streaming services like Hulu Plus, Netflix and Amazon Prime. For these users, subscribing to HBO Go in order to watch “Game of Thrones” would mean buying a cable subscription and a premium HBO subscription on top of that.

In some parts of the U.S., that could mean that potential customers would be paying as much as $70 a month just to watch “Game of Thrones” legally each week. This wouldn’t be the case if anyone could subscribe to HBO GO. It wouldn’t kill piracy completely, but it would certainly make a dent.

By opening up HBO GO to non-HBO subscribers, the company could boost its ratings and resumes each week.