The five-year veteran injured his knee during a non-contact drill last Wednesday. The on-site assessment was a torn anterior cruciate ligament and that diagnosis was confirmed on Friday by an MRI exam.
There is no urgency for a decision, but the Falcons could place Carpenter on the injured reserve list, by definition ending his 2004 season. Carpenter said last week that he felt he might be able to return by November and acknowledged frustration at the setback.
He had been working with the second-unit defense at the time of the injury.
Carpenter, 26, is a solid but underrated player, more resourceful than people think. An unrestricted free agent at the end of the '03 campaign, he re-upped with the Falcons two months ago, on a one-year deal with a $535,000 base salary and $25,000 signing bonus.
He has appeared in 68 career games and started in 46 of them. Carpenter started all 16 games for Atlanta in '02, began the 2003 season as the starting free safety, and then was benched along with the rest of the secondary at mid-season. Despite the demotion, he still tied for the team lead in interceptions, with three.
The former Virginia Tech standout began his career with the Buffalo Bills, earning a roster spot as an undrafted free agent in 1999. After three seasons with the Bills, he was not tendered a restricted free agent qualifying offer and signed with Atlanta, where he was reunited with then-defensive coordinator Wade Phillips.
For his career, Carpenter has 200 tackles, 12 interceptions and 21 passes defensed.
Len Pasquarelli is a senior NFL writer for ESPN.com.