Veteran defensive back Marlin Jackson left practice Tuesday with a ruptured Achilles tendon in his right leg, the Philadelphia Eagles announced, leaving the team even thinner at free safety.
The Eagles didn't provide a timeline for Jackson's return, but it's likely a season-ending injury.
Jackson, who signed a two-year contract with the Eagles as a free agent, is coming off two season-ending knee injuries he sustained with the Indianapolis Colts. He missed the second half of 2008 with a torn anterior cruciate ligament in his right knee and returned in 2009 before tearing the ACL in his left knee during a November practice.
Since letting Brian Dawkins leave for the Denver Broncos in free agency last year, the Eagles have had issues at free safety. They tried second-year pro Quintin Demps, rookie Victor Harris and veteran Sean Jones at that position in 2009.
Macho Harris likely will move to free safety, according to the Philadelphia Inquirer. The Eagles also have rookie safety Nate Allen, a second-round pick in the April draft.
The Associated Press contributed to this report.