Before I'd cut either Ebner or Fells I'd cut Marquis Cole and Jeff Tarpinian.
Why?
The startable LBs are now 6 deep, Mayo, Hightower, Spikes, Collins, Fletcher and A. Wilson. The ST only LBs, who made the roster when there was only the Big 3, will have to yield to them. Plus Fletcher and Collins are playing ST too.
Marquis Cole is an abomination as a CB. He is older and he made the club because he is the #2 gunner on ST, and there were not enough genuine CBs, last season. But Logan Ryan has been ably playing the #2 gunner slot on ST; and he is a legitimate and genuine CB even if he is a raw rookie. So he has much more upside.
Ebner was the second best ST on the club last season, just barely behind Slater. Plus he has more upside. Tavon and Duran are good ST players too, so we are not bereft on ST, with dumping several ST-only guys, and replacing them with two way potential players.