Panthers know what they have to work with on offense

As unspectacular as Cam Newton’s first quarter of work was (2-of-6, 17 yards passing, 2-16 rushing and a field goal drive), Panthers fans can take solace in the fact he’ll have plenty of time to get acclimated. That’s partly because with this afternoon’s five-year, $36.5 million contract extension for backup running back Jonathan Stewart, this…