I think there is a VERY good chance that we have at least two different starters on the OL. Adams is going to be there if he is recovered from his injury. Rivera is going to be there because of his salary and his prior history. LA will probably be there, but I completely disagree that he makes too much to be replaced. We will gain a big chunk of salary cap room....PLENTY of room to get an adequate replacement. And if Peterman can only play LG, then maybe it's the time to see if he can play at all. Allen can still dominate his opponent, but only if they stay right in front of him.
At C, we HAVE to upgrade. There is no way around it. I like Johnson quite a bit, and I don't think his play was nearly as bad as many suggest, but he is definitely not the total package. The one clear target should be Bentley. Young, and already one of the best in the league, it's unknown whether NO will pay him as a franchise player. There are some other centers that would be an upgrade to Johnson in free agency.
At RT, we will bring in competition without a doubt. I think Petitti will be better. He will have a year of weight training, not weight loss. He will have a year to work on his footwork, which was a drastic change for a guy who has always played LT. And hopefully he will be healthy. He got much worse when he suffered the knee and ankle injury in Detroit. It was a high ankle sprain, one of the most difficult injuries to play with.
There is a bonanza of tackle talent in the first round of this draft. Get one if you don't get another free agent to compete. We do have the several vets that we brought in last year. With a full training camp, we will see if they can compete.
Here is what I would do though. If the best tackle is a LT, then bring him in at LT and let him work there. Consider moving Flo to right tackle. Do not make the rookie make the change...if you do, there is no chance that he will be effective. Flo will be coming off an injury that could rob him of some of his speed and agility, which were never top notch. He has played right tackle and would have no problem returning there. We improve RT by leaps and bounds, making it a strength, rather than a weakness. And the LT would be playing his same position, would be able to get the majority of any TE or RB help against the pass rush.