The move is more of an indictment on Ugoh's play than it is an endorsement of Johnson's excellence.
If Ugoh can't win back his job, if he can't begin to live up to the level the Colts expect of a high-second-round pick, this offense is going to have some issues. Johnson is a nice player -- a career plug-in who replaced Ryan Diem and played brilliantly in the Colts' Super Bowl victory over Chicago -- but he's not the guy you want protecting Peyton Manning's blindside week in and week out.
This is a monster year for this offensive line, which got beat up by injuries last season and failed to make holes for a poor running game. One of the reasons Howard Mudd returned for one final year was to fix what was broken. The idea that Caldwell is only doing this to motivate Ugoh is silly; this group is going to help determine whether the Colts are Super Bowl material or first-round roadkill. Caldwell isn't on this job to play mind games.
You can say it's silly all you want, Bob. The idea that CJ is better at LT than Ugoh is what is truly silly. He isn't. No one believes that. Even if it's not a ploy, it's not a move that will last more than a few weeks into the season. Johnson will be a disaster and they'll have to move him. It's only a question of how many games they lose first.