Panthers sign Davis to shore up thin linebacker crew

With middle linebacker Dan Morgan already ruled out for a fourth straight contest due to the after-effects of the concussion he suffered in the opening game of the year, the Carolina Panthers on Thursday signed veteran linebacker Rod Davis to address a shortage at the position.

Morgan did not practice again on Thursday and, with Carolina officials demonstrating caution as he recovers from the fourth documented concussion of his six-year career, there is no definite timetable for his return to the field. The former first-round draft choice did debunk rumors earlier this week that he might be forced to retire because of the cumulative effects of the concussions.

The continued absence of Morgan has forced the Panthers to shuffle their linebacker corps, with some backups now getting considerably more snaps from scrimmage than anticipated, and the addition of Davis should allow them to at least reduce their workload on special teams units.

To create a roster spot for Davis, the team placed tight end Mike Seidman, who suffered a torn anterior cruciate ligament two weeks ago, on season-ending injured reserve. Seidman had started in three of four games in 2006, but did not have a reception. The torn ligament was discovered earlier this week.

Carolina still has three tight ends on its roster. Team officials spent the past few days exploring their roster options, but principally seeking a young veteran linebacker who could contribute quickly on special teams.

Davis, 25, is a versatile linebacker who played two seasons with the Minnesota Vikings and was in camp with them this summer, before being released. A fifth-round pick in the 2004 draft, Davis has played as a reserve at all three linebacker spots and is also a standout special teams performer.

The former Southern Mississippi star appeared in 30 games with the Vikings, including one start. He has 32 tackles and one forced fumble on defense, and 23 special teams tackles.

In an unrelated matter, starting center Justin Hartwig, who returned to the field Wednesday after missing three games with a groin injury, did not participate in Thursday's practice. Hartwig is listed as questionable on the team's injury report.

Len Pasquarelli is a senior NFL writer for ESPN.com. To check out Len's chat archive, click hereInsider.