Ron Rivera has an ambitious goal for Cam Newton in 2016

The Carolina Panthers had an outstanding 2015 season, thanks in large part to Cam Newton's MVP campaign. But there's no time to rest on their laurels.

As the Panthers open offseason workouts this week, coach Ron Rivera is letting reporters know that he expects Newton to be an improved player in 2016 -- and not just in the margins. According to Rivera, Newton's capable of being better in literally every aspect of the game.

Via ESPN.com:

"Everything," Rivera said during Tuesday's first practice of Phase 3 offseason workouts. "Last year we talked about developing certain throws and he did that. Can he develop and get better physically? Yeah. His skill set can continue to get better.

"I know they're constantly working on his technique, his footwork, his delivery ... and then again work on the mental aspect as well. I'm not putting anybody on blast. I'm just challenging him that he can become a better football player."

That might seem like a ridiculous goal, but stick with us for a minute. Newton could very well be approaching his peak as a player. 2016 will be his sixth season in the league, which is about the time that elite quarterbacks take a leap into a stratosphere of their very own. Peyton Manning posted his best statistical season in his seventh year on the job after experiencing a noticeable improvement in his sixth season. Tom Brady started to figure out NFL defenses in his fifth and sixth seasons, paving the way for the 50-touchdown performance that came in his eigth season.

On a general level, then, Newton is right on track to meet Rivera's challenge. But there's one thing Newton must do to improve his all-around game.

His completion percentage has to get better -- and ASAP. Out of QBs with at least eight starts last year, Newton was 27th in the league in completion percentage, trailing even the zombified Peyton Manning. That hasn't been a huge problem to this point, since Newton rips off such massive yardage when he does find a receiver (seventh in the league in yards per attempt in 2015). Of the top 10 QBs in YPA, however, Newton had by far the worst completion percentage. Taking shots down the field doesn't have to mean a sub-60-percent completion percentage. Even just a few more successful passes per game could elevate Newton's play to a Hall of Fame level.

As Newton's accuracy improves, the rest of his game should follow. Defenses will be less willing to load up on the Carolina running game, allowing Newton to continue to refine his decision-making. The Panthers quarterback is an absolute weapon on the field with his ability to take off or stop on a dime for a ridiculous pass, but he can also get himself into trouble when he picks the wrong moment to keep it on the ground. If he's able to keep Carolina in manageable situations rather than third-and-long after a missed throw, however, his decisions become easier, and he'll make the right one more often.

And if he can improve his approach to postgame interviews, then Newton will really have improved on everything, just like his coach wants.