If Mankins isn’t ready and Waters doesn’t report for the season, there are a number of combinations the Patriots could employ that have center/guard Dan Connolly, center Dan Koppen, center/guard Ryan Wendell, center/guard Nick McDonald and/or guard Donald Thomas as part of the interior mix. Those are the next players in line, with Connolly the top talent of the group. All have starting experience in the NFL, so it’s not as if the cupboard is bare. But it’s not the desired result.