In a conversation with ESPN's John Keim at the NFL owners meetings in Orlando, Fla., this week, McCoy reaffirmed that Rivers remains the team's franchise quarterback for the long haul.
Further, McCoy believes Rivers' improved performance is not an aberration.
"He should start off where he finished and have the type of year he had last year," McCoy said. "Our team will only improve. There were a lot of first times for our team also, in a new system. There's things you're learning -- you practice things all the time but they may not be against a certain coverage.
"He was learning as we were going during the year. As time goes along you put in a new play, maybe it's a play out of a new formation, or someone else is running it, Ladarius [Green] is running it versus one of the receivers. You're still learning about one another and your system every week.
"We said the first day sitting here last year [that] Philip Rivers was not the problem. It was everyone else around him playing better. He'll be the first one to tell you also that he needed to play better. He couldn't make certain decisions he made. That's the quarterback position. You'll throw interceptions sometimes. He's going to make more good decisions than bad decisions."
McCoy said even with former offensive coordinator Ken Whisenhunt moving on and taking the head coaching job in Tennessee, he still expects Rivers to have similar success under new offensive coordinator Frank Reich.
"The system's in place," McCoy said. "We put a system in place last year to be there for the long haul, and we all sat down and there were good offensive minds in there and there are still some good offensive minds in there. We knew this could happen at this point in time that Ken could leave. But that's what happens in this profession. We have a great staff in place. We added [tight ends coach] Pete Metzelaars and he will be great for the offense also. We built the system for the long haul."