At this point, the two logical options are center or right guard.
If the answer to that question is Ruddy, then McKinney should be able to supplant Perry as the starting right guard.
If Perry outplays Ruddy, then you might be looking at a situation where McKinney starts at center and Perry keeps his job at right guard.
At this point, we would think the odds favor McKinney replacing Perry at right guard.
If that happens, it's difficult to envision the Dolphins keeping Perry around. He refused to redo his contract in the offseason and makes too much money to be a backup.
One thing for certain, the offensive line will be fun to watch this summer.