The Panthers made improving their special teams a major offseason focus.

At times during the preseason, it was hard to tell.

The Panthers gave up a 90-yard touchdown return to Houston’s Trindon Holliday on their first kickoff of the preseason. In their final exhibition last week at Pittsburgh, the Panthers allowed Chris Rainey to bring back two punts for long touchdowns, although both were called back on holding penalties.

Despite the coverage issues, coach Ron Rivera said he feels “much better” about the team’s special teams core compared to last season, when the Panthers ranked near the bottom in nearly every category.

The Panthers overhauled the unit. They brought in Richard Rodgers, Rivera’s teammate at Cal, to assist special teams coordinator Brian Murphy.

They signed three free agents – fullback Mike Tolbert, safety Haruki Nakamura and linebacker Kenny Onatolu – to add proven players to the coverage and return teams. They drafted Arkansas punt returner Joe Adams in the fourth round to replace Armanti Edwards, who averaged just 5.5 yards a return in 2011.

And they went with a youth movement at punter and kicker, releasing punter Jason Baker in the offseason and Olindo Mare last month to make room for first-year players Brad Nortman and Justin Medlock.

Panthers general manager Marty Hurney said Nortman and Medlock won their jobs in large part because of their leg strength. In some cases, Nortman’s foot has been too strong.

“Our punter does such a good job of driving the ball. He’s hitting 60-yard balls,” Nakamura said Tuesday. “You don’t want to say he’s outkicking his coverage because we have some pretty good coverage players.

“That’s just a matter of being more disciplined. Seeing where the ball is landing, see where the returner’s heading before he catches the ball because on a longer kick we’re going to have to adjust our lanes.”

Rivera was not alarmed by the long runbacks by the Steelers’ Rainey because in both cases the Panthers had someone in position to make the play before he was pulled down by a Pittsburgh player, drawing penalties.

“We did miss a couple tackles, but the primary guy was the guy who got pulled out of the way and it’s unfortunate,” Rivera said. “You don’t want those things to happen and those are things that we most certainly looked at and stress and try to get corrected.”

Several of the coverage team members against Pittsburgh have since been released.

Safety Reggie Smith, another offseason acquisition with a strong special teams background, was among the cuts last week. Instead of keeping Smith, the Panthers traded a future seventh-round pick for San Francisco safety Colin Jones, whom Rivera called a “special teams fiend.”

“I tend to think I’m pretty fast. I just like running down the field,” Jones said. “If I could pick a job, it would be playing special teams in the NFL. That’s what I like to do.”

Onatolu, who played on Murphy’s special teams for two years in Minnesota, also has a passion for it. That’s why he had trouble watching the coverage breakdowns against Pittsburgh – penalties or not – while watching the game from Charlotte, where he was rehabbing a hamstring injury.

“That definitely doesn’t sit well with me, even when I was on my couch watching the game on TV,” said Onatolu, who has returned to practice. “I was a little disappointed in that. Guys like me and (backup linebacker) Jordan Senn, we take it to heart.”

Senn’s 11 special teams tackles last season were second on the team. Senn was one of the few consistent contributors to a unit that, like the Panthers’ defense, was decimated by injuries.

The Panthers gave up a franchise-worst three punt returns for touchdowns, including an 89-yarder by Arizona’s Patrick Peterson that was the difference in a 28-21, Week 1 loss.

The Panthers want to avoid a similar start this year with their new punter. Nakamura, the starting free safety who will continue to play special teams, said Nortman needs to keep booming punts.

Nakamura is confident the coverage guys will catch up.

“For a kid to be kicking it that far with confidence, he could be our biggest weapon on our team,” Nakamura said. “You emphasize changing the field. And the one way you change the field, you’ve got to have a good kick. And he’s kicking it 60 yards in the air. You can’t get much better than that.”