JT is fine. Saban is doing exactly as he promised, which is featuring Zach and JT in his defense. It is obvious from the veteran interviews after OTAs that phins.com's guest columnist Mark Dell'Ebert or whatever had it right when he called out Saban's "3-4" defense. We'll have a LNT who will play off the center's right shoulder pad, a RDT who will play on top of the LG, a RDE who will play wide of the LT at all times (this will be JT), a LDE who will also play on the outside shoulder of the RT, a SSLB who will line up close to the line of scrimmage outside the LDE, a MLB who will play behind the NT and will have a very physical gap-shooting role, and a WSLB who will "drag" or "scrape" the flow of the play and be relatively free to roam the field and make tackles (this will be Zach).
My guess is that Roth and Bowens will rotate in at LDE and RDE as well as possibly SSLB, Holliday will rotate in at RDT and LDE, Carter will start at LDE and rotate over to RDT, Chester will start at LNT but sub out for Bowens, Vickerson will be inactive but would play LNT and RDT when activated, Zgonina will rotate in at RDT with Holliday (may actually start at RDT), Junior will start at MLB with Channing Crowder primary backup, Zach at WSLB with Channing Crowder primary backup, Spragan at SSLB with Roth, D.Bowens, and Crowder backing him up.
The only hole in the roster is I don't know who starts at RDT. I don't like the idea of having Chester and Tim Bowens on the field at the same time. I don't really love the idea of Zgonina starting there at RDT either. I also am not in love with moving Carter over there too often and taking him away from his LDE role, even though it would mean more playing time for two very good ends in D.Bowens and Roth. I'm not terribly enthused with the idea of Holliday playing there either. But, what you lack in a consistent starter, I guess you make up for with a healthy rotation. I'm just hoping that with Spragan being a bigger presence at SSLB than Greenwood (literally bigger, not necessarily better) and having a safety more involved in the middle, we'll be able to stop the run without giving up a whole ton of over the top passes.