They have Gaines and Robinson to play at NT so SJD is covered. Noteboom has played well every time he's given the opportunity at LT. He's their LT of the future and has been since the day he was drafted. This is a good opportunity to get him to gel with his fellow OL. IMO the weak link inside is the inconsistent play of Edwards.
I'm actually glad Havenstein is having a good season. He will be good trade bait next year. That will clear over $9M in cap. Also, he needs to play well if the Rams are to truly make a SB run. Teams have to blitz to get pressure because this OL has shown they have been able to handle good front 4 DLs.
I don't see them missing a beat with Noteboom. Also, I think Alaric will be ready to play RT next year. He looked very good in preseason and he's been redshirted this season, and will have another full OTA and TC next year. He and Noteboom should finally set this OL up.