NXT Star Sami Zayn "will be competing" at the NXT Takeover: Unstoppable show according to an update provided by Triple H during a press call today. 

"He's been cleared, he will be in the ring tomorrow night with Kevin Owens" said Hunter. 

There was some concern Zayn might not be cleared after a shoulder injury prior to his match against John Cena on Raw a couple weeks ago.