Two reasons now point to Zoom being Jay Garrick from the future.
The first being the Hunter Zoloman connection with his doppelganger on Earth 1.
The second which was hinted at massively in this ep when talking about Velocity 6/7 - Jay has a craving to become faster by any means possible, a connection he shares with Zoom. He explained it as if it were an addiction, and it's entirely possible that Jay is the 'good' version before he is driven mad by his addiction later in the future and turns into Zoom.
My other theory is that Eddie could be the other conceivable suspect. We didn't spot his doppelganger on Earth 2, so where is he? More intriguingly, why was his body sucked into the portal after he killed himself in S1? The writers deliberately added that for a reason - could it have something to do with Zoom?
Boooom! My theory about Jay takes another step towards coming true.
The man in the mask spelt out 'Jay' to indicate one of two things...
1. He is the actual Jay Garrick under the iron mask being held captive by Zoom - an evil Jay perhaps, or even an evil Eddie?
OR
2. It isn't Jay under the iron mask, but instead someone else (Eddie) indicating that Jay is actually Zoom - perhaps due to going crazy with his insatiable need for speed force.
I still believe that the first theory will be true... but with a twist!
The Jay Garrick that has been helping out Barry and co is actually the older evil version of Jay (Hunter Zoloman) that has become Zoom later on in the future timeline of E1. In order to blend in and look the same age as the captive Jay, Zoloman has stolen his youthful facial and body features - similar to how Eobard used that technology to steal Wells body on E1.
The reason Zoloman could be keeping his younger counterpart captive could be something to do with the cell degeneration illness that Caitlyn uncovered, and he was harvesting his DNA to replicate and replace his own dying cells... that is until Caitlyn's development of Velocity 9 showed him a method of staying alive without further damaging his cells.
As for Jay being impaled with Zoom's arm through the portal, it may be a speed mirage similar to Reverse-Flash's ability to fight with himself. I just found it way too convenient that he was standing unnecessarily close to the portal. You could just tell something was going to happen.





