CHARLOTTE, N.C. (AP) There are times Ron Rivera watches Cam Newton throw a football and thinks he can be one of the best quarterbacks of all time. And there are other times the Panthers' coach studies Newton's release and says to himself, ''Aw c'mon, you have to have better footwork.''
Rivera would like to see Newton improve the consistency of his throwing mechanics as the Panthers look toward the future.
Newton, in his sixth NFL season, has completed a career-low 53.5 percent of his passes this season and has failed to complete 50 percent of his passes in five of the last six games while battling soreness in his right throwing shoulder.
The Panthers are 6-9 and won't make the playoffs after reaching the Super Bowl last season. They wrap up the season Sunday at Tampa Bay.
Newton, last year's MVP, has seen a dramatic drop off in his production, throwing just 18 touchdown passes with 11 interceptions one year after tossing a career-high 35 TDs with 10 INTs.
Rivera attributes some of Newton's issues with accuracy to an offensive line that struggled to protect him early on - 21 sacks in his first seven starts - and a late-season shoulder injury that has left him limited in practice and at times grimacing in pain after taking a hit on game day. Over the past six games Newton has completed 91 of 201 passes (or 45.2 percent) while playing behind an offensive line without two-time All-Pro center Ryan Kalil and left tackle Michael Oher, both of whom are on injured reserve.
''I think a lot of it is reflective on how much pressure he received earlier in the year,'' Rivera said. ''I think sometimes it kind of sets you back a little bit.''
Panthers offensive coordinator Mike Shula said Monday that Newton's struggles are a team issue that goes far beyond the play of the quarterback.
''We as a passing offense need to be better,'' Shula said. ''Coaching, throwing, catching, protecting, getting to the right spots. ... You can't look at a completion percentage and say, `Oh, he's not very accurate.'''
Shula has heard the criticism over Newton's throwing mechanics and believes everyone can work to get better.
But Shula was quick to add that ''every quarterback ''has his own style,'' and Newton is no different.
''You hear about him throwing off his back foot, but there are a lot of guys who make throws off their back foot,'' Shula said of the 6-foot-5, 245-pound Newton. ''That's not how you teach it but sometimes you have to do that. Cam has the ability to do that and make some great throws whereas other guys couldn't do that.''
Shula said Newton is taught to stay balanced, but if he can't do that while under duress then the key is get the throwing shoulder all the way through on his release and making sure he follows through to the intended target.
''If you don't, your accuracy goes down,'' Shula said.
Shula remains extremely confident in Newton's ability - and his mechanics as a passer - despite the criticism.
''You don't have to have the ability to step up and still make accurate throws,'' Shula said. ''You teach a good foundation, a good base so even if you can't step up (because of pressure) you are sitting there with a good base where you can transfer your weight.''
NOTES: Rivera said he concerns about the availability wide receiver Devin Funchess (knee), safety Tre Boston (knee) and defensive end Charles Johnson (hamstring) for Sunday's game at Tampa Bay.
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