I feel sorry for the guy. Unlike Joe UDFA, he has a high profile because of his draft rank. I know that at 22 or so if I was visibly and totally failing at my chosen career it would not help my mindset to have millions of people watching me fail and deriding my inept efforts. As close to unrecoverable mentally as you can get.
Pats would be doing him a favor trading him for a conditional 7th or something. Fresh start with less visible pressure.
That said, I'd give him at least 2 more pre-season game looks hoping for a pony.
Here's the thing, though.
I don't know for a fact that the Pats are trying to develop Cy Jones into even a regular rotational CB at the moment. Probably when they drafted him, they thought he could develop into one eventually, and the coaches may still think so, for all I know. But, right now, there really may not be anywhere near as much pressure of expectations coming at him from the coaches as there is from the fans, many of whom see him only as "SECOND ROUND PICK Cyrus Jones".
Another thing is that I've only seen Cyrus deployed in the RCB role and on the inside - never at LCB. Rowe and Ryan switched back and forth in the RCB/"slot" roles for awhile last season, with Ryan eventually becoming mostly the inside guy, it seems to me.
Anyway, guys who can cover the boundary well on the right side of the defense have historically been tough to come by for the Pats, especially those who can do so without safety help over the top. Learning the footwork and body-positioning that are exactly the reverse of what the LCB does is not something that every CB excels at, apparently.
Ryan was pretty good at RCB (though he wasn't left on an island all that often, IIRC, and Rowe seems pretty good. Gilmore seems very good, and he's also been pretty good at LCB and sometimes even on the inside - a relatively rare positional versatility.
So, the coaches may merely be looking for Jones to become an "adequate" injury-backup RCB (with consistent deep safety help) this season.
Obviously, what the coaches are actually thinking is a total unknown to me, since I'm not a mind reader.