...the night after the Rumble. WWE feel he'd get a big pop from Orlando in the Rumble match, but want to present him as a big deal and so having him debut in a match he has no chance of winning might be counter-productive. They don't think his pop would be any smaller the next night in Miami.
I mean, I GET the thinking...but the Rumble is an event that draws even lapsed viewers and therefore if they think Styles showing up alone would cause people to tune in the next night it would be worth it. Let him have a good showing in the Rumble and maybe make a key elimination or two and it wouldn't hurt Styles at all.