Zoom has been prominently shown as the main villain of "The Flash" season 2, and in episode 14, "Escape from Earth-2," the character nearly defeated Team Flash while also kidnapping or killing Jay Garrick (Teddy Sears) at the very end of the episode. However, according to Screen Rant, it is now entirely possible that Jay is Zoom.
Entertainment Weekly also postulated this theory after the episode released, pointing out that Jay already revealed Zoom never stole Jay's speed when the former tossed the latter to Earth-1. In a previous episode Jay revealed to Caitlin (Danielle Panabaker) that he lost his speed due to his addiction to Velocity-6 drugs that increased his powers.
By that statement, it is established that Jay Garrick is addicted to getting faster. This is even more apparent in the previous episode as the Velocity-9 makes Jay temporarily lose his sense the moment he once again experiences what it is like to be a speedster.
The episode also had a person imprisoned in Zoom's dungeon, wearing a mask and devoid of the ability to speak. Instead, this character resorted to using tap codes to speak to Barry Allen aka the Flash (Grant Gustin) and to Harrison's (Tom Cavanagh) daughter.
Barry is able to decipher that the prisoner is saying the word "Jay" but shakes his head in frustration when Barry states that Jay is safe and is on Earth-1. It is speculated that this could mean the prisoner is the real Jay Garrick and that the one on Earth-1 is someone else.
According to the report, this could mean that Zoom is in fact the future version of Jay Garrick. Zoom, over time, is speculated to have gotten so addicted to speed due to the success of Velocity-9 that he now wants the ultimate form of speed satisfaction, which he can only get by stealing The Flash's powers.
The report does point out that it doesn't explain why Zoom would kidnap or kill his younger self, implying that this theory could still be shot down.
