CHARLOTTE, N.C. (AP) - A quick glimpse at the numbers suggests the Panthers should focus on upgrading their defense next offseason.

But that's not necessarily the team's thinking as it begins to look ahead to 2012.

Although the Panthers rank 23rd in the NFL in total defense this year - as opposed to fifth on offense - general manager Marty Hurney and coach Ron Rivera feel the defense is much improved over the last month.

The Panthers (5-9) have held three of their last four opponents to fewer than 20 points entering Sunday's game against Tampa Bay (4-10).

Combine those numbers with the fact that the Panthers get middle linebacker Jon Beason and four other potential starters back from injured reserve and a complete overhaul of the defense may not be as big of a priority as some might think.

"I think the defense will make great strides next year," Hurney said. "I think we still have a good core group intact. You always look to add some pieces, but I think it's encouraging what we've seen the last four weeks."

Hurney and Rivera attribute the improvement on defense during that span to keeping the same starting lineup intact for most of that time.

"We really haven't had the continuity we'd have liked to have from the beginning," Rivera said.

That's an understatement.

The Panthers have been decimated by injuries on defense and the starting lineup has been a revolving door.

It started when they lost veteran defensive tackle Ron Edwards in training camp, forcing them to start the season with a pair of rookies - Sione Fua and Terrell McClain - in the middle.

Beason torn his left Achilles tendon in the season opener and outside linebacker Thomas Davis re-tore his left ACL the following week against Green Bay, leaving the team void of its two defensive leaders.

As the season progressed the injuries kept mounting.

Linebackers Thomas Williams and Jason Phillips landed on injured reserve after being handed starting roles. Later, McClain and Fua were lost to season-ending injuries, continuing the season-long trend.

Despite all of that the Panthers were able to limit the playoff-bound Texans to one touchdown in a 28-13 win last Sunday.

"I think just by getting some of those guys back from injuries next year and with the experience some of these (backup) players have gained this season it will naturally help us down the road," Hurney said.

Hurney said the Panthers will look to upgrade in all three phases - offense, defense and special teams - through the draft and free agency, but doesn't necessarily view one as more pressing than the others.

So even though the offense has made magnificent strides in going from last in the league in 2010 to fifth this year behind Cam Newton, Hurney said he won't rule out adding pieces to help his rookie quarterback.

"I think you always want to keep your strengths strong," he said.

Defensively, linebacker is the biggest area of concern because Dan Connor and Jordan Senn, who started the season as backups but have played well in starting roles, are unrestricted free agents. There's also the unsettled the future of Davis, who's due an $8 million signing bonus in March - one he's won't get after tearing his ACL three times in three years.

Getting Beason back should be huge.

Beason said Tuesday he's ahead of schedule in his rehab and "without question" plans to participate in the team's first minicamp next spring.

"I'll have a helmet on come April," Beason said.

He started running recently in the pool, a big step in the recovery process.

That's terrific news for the Panthers.

A three-time Pro Bowl selection and the defense's unquestioned emotional leader on the field, Beason led the Panthers in tackles for four straight seasons prior to suffering a season-ending injury in the season opener against the Cardinals.

The defense was going to be geared around Beason, although that changed.

"Do we need (to add) a few free agents? I don't know, maybe," Beason said. "But to tell you truth I've been impressed with the way guys have filled in. Guys who weren't even here in camp. I think we're improving this year, guys are learning the defense and that's going to carry over to next season. On top of that we get a lot of guys back from injuries, so I think the future is bright."

Notes: The Panthers didn't have to release an injury report Tuesday but Rivera said cornerback Captain Munnerlyn (left hamstring) and defensive end Charles Johnson (back) were held out of practice Tuesday.