Jenkins, a fifth-year pro, was really blossoming into a star end opposite All-Pro Aaron Kampman. He suffered a torn pectoral muscle during Sunday's 30-21 loss at Tampa Bay. The injury will require surgery and around three months of recovery time, making it pointless for Jenkins to remain on the active roster.
For Green Bay, this is a really bad break. Jenkins and Kampman were clearly the bright spots on a defensive line that has struggled to make plays. The trade of tackle Corey Williams to Cleveland before the NFL Draft, combined with the injury problems involving 2007 first-round pick Justin Harrell, really damaged the interior line.
The Packers have already slipped to 27th in the NFL in run defense (almost 160 yards per game, or more than 60 ahead of last year's total), and losing Jenkins isn't going to help.
It's expected that Mike Montgomery and rookie Jeremy Thompson will share time at Jenkins' end position. There will also be pressure on veteran Kabeer Gbaja-Biamila to provide pass pressure.
Of more concern for the Packers than the run support in that spot may be the pass rush Jenkins provides from the interior on passing downs. Montgomery and Thompson aren't likely to be very effective at all in that role, and the Packers don't have any tackles who are good at getting upfield.