CHARLOTTE, N.C. -- The Carolina Panthers entered training camp with a new defensive coordinator, a more aggressive scheme and plenty of motivation in the locker room to erase memories of their late-season slide in 2008.
Halfway through the preseason, injuries are derailing their plans.
Jon Beason, Carolina's middle linebacker, leading tackler and defensive leader, is the latest concern. He left Saturday's preseason loss to Miami with a left knee injury.
Beason's agent, Drew Rosenhaus, said the injury was a strained medial collateral ligament, and he was optimistic his client could return for the start of the regular season. Rosenhaus made his comments late Sunday on his weekly appearance on WSVN-TV in Miami.
A team spokesman declined to reveal the results of a scheduled MRI exam. Rosenhaus and Panthers general manager Marty Hurney didn't return messages. Beason also didn't update his Twitter page or Web site.
Defensive tackle Maake Kemoeatu's season was ended by a torn Achilles tendon earlier in training camp.
The lack of depth behind Beason, Carolina's leading tackler the past two seasons, is glaring. Dan Connor, who played three NFL games as a rookie before tearing his ACL last season, is his backup.
Beason said he stayed in the game for a couple of plays after he was injured.
"I was getting off a block and I'm not sure if someone came at me intentionally or if they fell on it," Beason said. "I'm assuming someone fell on it."
The Panthers used the 25th pick in the 2007 draft on Beason, who starred at Miami. He set a team record with 160 tackles his rookie year and was selected to his first Pro Bowl last season, when he had 159 tackles and tied for the team lead with three interceptions.
Beason's absence would provide another obstacle for coordinator Ron Meeks, who ran Indianapolis' defense the past seven years. He took over a team that gave up 30 or more points in five of the final seven games last season, and was already facing a severe depth shortage on the defensive line.
Nick Hayden, who has two games of NFL experience, and undrafted rookie Marlon Favorite have been filling in for Kemoeatu without success. The Dolphins rushed for 141 yards Saturday and averaged 5.2 yards per carry in the first half. That came after the New York Giants rushed for 139 yards in Carolina's preseason opener.
The defense isn't the only area lacking depth, largely because of the $18 million salary cap figure of Pro Bowl defensive end Julius Peppers.
Peppers takes up more than 14 percent of the cap, leaving little room for high-priced veteran backups -- and even experienced long-snappers.
The Panthers saved money by not re-signing Jason Kyle and trading for the cheaper J.J. Jansen. Working from a spot on the dirt baseball cutout Saturday, the second-year pro sailed a snap so high that holder Jason Baker had to stand to catch it, aborting John Kasay's 42-yard field goal attempt.
"You get to work on the dirt a little bit, and we struggled with that," coach John Fox said. "We have a young snapper who had to deal with that for the first time. So hopefully, that's what preseason games are for, so you learn from them, particularly young players."
Carolina's decision not to re-sign veteran return man Mark Jones had also produced uncertainty. Rookies Captain Munnerlyn and Larry Beavers and Ryne Robinson all muffed or fumbled punt returns Saturday, with Robinson's turnover leading to Miami's decisive touchdown.
"I've got to work on holding the ball," said Munnerlyn, who had a 58-yard return earlier in the game. "All of us guys back there. We fumbled too many punt returns."
The latest inexperienced player to land an important role is Connor, a 2008 third-round pick from Penn State. He'll likely be asked to fill in for Beason in Saturday's exhibition against Baltimore.
Connor has had a good preseason. He recorded six tackles against the Dolphins and a team-high eight a week earlier against the Giants.
But it means Meeks has a lot to accomplish with the Sept. 13 opener against Philadelphia looming.
"It's a new scheme so we have to get adjusted," Peppers said. "That's what the preseason is for."