The last real options for the Panthers to improve their OL have ended.
RG Brandon Moore just announced his retirement (updated: he is now disputing this).
RT Demetress Bell - a better fit for the Panthers' scheme than Winston though not as good a player as Winston - has signed with the Cowboys.
There is no one else particularly regarded available in free agency. There was the hope that someone would get released during training camp that the Panthers could pick up, but since all the salary cap related cuts took place long ago, realistically the chances of somebody good losing a training camp battle and being released outright rather than simply being shifted to another part of the OL or being held onto for depth overestimates the amount of quality OLs in the NFL ... not enough for even the few teams with good OLs to put a quality lineman out on the street.
Another thing to point out: Winston, Moore and Bell at least have been available the entire offseason, and the Panthers have had enough money to sign them for several months, at least since DeAngelo Williams redid his contract in may. Yet the Panthers made no attempts to sign any of them, or for that matter other than Wharton anybody else. It is true that Winston and Moore were seeking multi-year deals, but the Panthers were - for example - not in position to be able to strike a deal with Winston when he finally abandoned that position the way that the Cardinals were. Even Rivera stating that Edmund Kugbila is still out of shape did not cause the Panthers to go out and acquire more help.
Since the only thing that the Panthers have done this offseason to help the OL was draft Kugbila and move Nate Chandler from DT to OT, it may well be that the Panthers think that the OL isn't that bad. Perhaps they are basing it on the last 8 games last year? Well consider it: they have Pro Bowlers at LT and C and a 2nd year 2nd round pick at LG. If Byron Bell continues to improve at RT then the OL is solid. Or at least no bigger an area for concern than WR, DT, CB and safety were at the beginning of this offseason.
Or maybe they prefer long term solutions for the OL next year to short term quick fixes this year. In either case, it looks as if they are going to stand pat, and further as if it was their plan all along. And I have to admit: carrying over cap room for next season sounds a lot better than using it on Wharton, who not only is injured but was very much part of the OL problems that the Panthers had in 2011 when he started 16 games. That experience motivated the Panthers to use a 2nd rounder on an interior OL in the first place. The same may be true of Moore: there is a reason why no one wants to give him the 2-3 year deal that he wants, so the Panthers should not step up and give him the deal that no one else wants to. Winston is another story, but he is a zone-blocking RT who won't fit the Panthers' rushing attack. Still, you have to figure that he would have been perfect for the Redskins as they run a zone blocking scheme- and Kyle Shanahan coached Winston when he was with the Texans - yet they didn't want him either.
The Panthers' pretty much standing pat except for adding a developmental prospect is not ideal, but it is preferable to throwing a bunch of money at guys that other teams passed up also.