SPARTANBURG, S.C. -- A daily review of the hot topics coming out of the Carolina Panthers training camp:

• Cam Newton overthrows a pass off the outreached fingertips of wide receiver Jerricho Cotchery. Newton throws a pass high and wide to tight end Greg Olsen. Newton throws high again. Yes, the franchise quarterback struggled early on this rainy Thursday morning. It had nothing to do with his left ankle, on which he underwent surgery in March. Asked if the weather had anything to do with it, coach Ron Rivera emphatically and sternly said, "No.'' But the struggles were noticeable, enough that the Panthers ran a couple of segments again. "He was perfect," Rivera said of Newton the second time around. "Once he got into his rhythm, he practiced very well down the stretch." Newton was especially impressive on his final two-minute drills -- or 1:30, as the Panthers like to go with -- finishing a drive with a touchdown pass over the middle to Cotchery. Newton also was more active in talking to his wide receivers and tight ends about what they were doing as it related to him.

• With first-round draft pick Kelvin Benjamin (bruised left knee) out another day, former Wofford standout Brenton Bersin opened as the first-string slot receiver when the Panthers opened in team drills. Normally, Jason Avant or Cotchery line up there with Benjamin on the field. Bersin's presence shows just how far he has come from an undrafted free agent cut early in 2012 to making the practice squad a year ago. Rivera said Bersin could help the team and he wants to see how he does against the first-team defense. Tavarres King also had a good day of practice. Three straight, according to Rivera, as the Panthers look to rebuild at receiver. Meanwhile, Benjamin's rehab is coming along nicely from his knee injury. There's still no timetable for his return, only that he will be re-evaluated before Friday's practice. He is not expected to miss next week's preseason opener against Buffalo.

• With left tackle Jordan Gross retired, the Panthers are looking for more leadership out of center Ryan Kalil. Rivera has been impressed with the way the four-time Pro Bowl selection has been more vocal in camp. Kalil admits he doesn't like speaking to groups as much as Gross did, but there's no doubt his leadership up front will be key to how this rebuilt line performs.

• The Panthers practiced kickoff returns for the first time in camp. Wide receiver Tiquan Underwood and fullback Mike Tolbert were the first pair deep. The speedy Underwood was signed as a free agent wide receiver, but he hasn't done anything particularly noteworthy there. His best way to secure a roster spot might be as a return specialist. Tolbert's primary role on kickoffs is supposed to be as a blocker, but a couple of times, the 2013 Pro Bowl selection lined up as the primary returner. Rivera quickly reminded the player known as "Fat Guy" -- among other things -- that he should return kicks only in "emergency" situations.

• Outside linebacker Thomas Davis looked like he was searching for a contact early in practice as he and several trainers scoured the field. He actually lost a diamond earring. He stayed afterward looking for it, but no luck. Davis wasn't as much concerned with the earring as he was having to file an insurance claim on it. Maybe it will show up later, as his lost wedding ring once did.

• The Panthers practice at 9:25 a.m. again on Friday. The forecast is for more rain.