It looks like Greenberg WAS talking about EA Access as he responded to a followup e-mail to Polygon:
Greenberg followed up in an email to Polygon to say he means that Star Wars: Battlefront will be first on Xbox One thanks to EA Access, the Xbox One-only service where Electronic Arts makes big upcoming releases available to subscribers the weekend before they launch.
“I was referring to the fact that Xbox One is the only place you can play all new EA games before they launch, exclusively with EA Access,” Greenberg said, just to be clear.
So yes, you can play it first on Xbox One, but only if you have EA Access.
Microsoft and EA have quite the cozy relationship these days, it’s pay service, EA Access is an Xbox exclusive, which lets players get their hands on certain EA games early. Sometimes it’s just multiplayer and sometimes its a few hours of the single player. Well get your tin foil conspiracy hats ready because a recent tweet by Xbox executive Aaron Greenberg implies that Star Wars Battlefront may be a timed exclusive:
— Aaron Greenberg (@aarongreenberg) April 14, 2015
So either Microsoft either cut a very expensive deal to get Star Wars: Battlefront to show up first on Xbox One or more realistically, EA Access is going to put the Star Wars games front and center.
The game is expected to be shown off in the upcoming weeks.