SPARTANBURG, S.C. — It could have been the heat.
It could have been the fact that his best receiver had the day off.
More likely, as Panthers coach Ron Rivera pointed out, Cam Newtons bad day was a combination of his timing and reads being off.
Newton threw two interceptions, and nearly a third Tuesday in his worst practice of training camp.
Newton, the Panthers franchise quarterback, was picked off on the first play of a team passing drill by cornerback Captain Munnerlyn, who returned the interception for a touchdown.
Munnerlyn almost had another pick on a poor throw by Newton, who has had a good camp before Tuesday. Linebacker Chase Blackburn had the other interception on a Newton pass across the middle.
Secondary settling: Carolina expected to shuffle around its secondary this training camp, but after the third day in pads, it seems like the Panthers have settled on a group getting the majority of first-team reps.
Free safety Charles Godfrey entered camp as the only sure-fire starter in the defensive backfield, but Drayton Florence and Captain Munnerlyn have settled at first-team cornerbacks while Mike Mitchell has received the bulk of reps at strong safety lately.
Rivera also said Munnerlyn is in front of D.J. Moore at the nickel spot.
Rosario waived: Carolina signed former UNC tight end Zack Pianalto, while waiving Nelson Rosario.
At 6-foot-4, 250 pounds, Pianalto brings both size and pass-catching abilities to the Panthers tight end group. He grabbed four passes for 40 yards for Tampa Bay in 2011.
Greg Olsen and Ben Hartsock are 1-2 on the Panthers depth chart at the position.