Source: Ras-I Dowling has torn tendon

FOXBOROUGH, Mass. -- The New England Patriots on Saturday announced that cornerback Ras-I Dowling (hip) has been placed on injured reserve, while running back Kevin Faulk and defensive lineman Brandon Deaderick have been activated from the physically unable to perform list to the 53-man roster.

Dowling, a 2011 second-round pick, suffered the hip injury in Week 2 against the Chargers, and had not played since, despite practicing in the weeks prior to the team's ensuing four games.

A league source tells ESPNBoston.com's Mike Reiss that the plan was for Dowling to rest over the bye week, and then test his injured hip when the team returned to practice this week.

After returning to practice on Tuesday and Wednesday, Dowling felt extreme discomfort, and an MRI revealed that he had torn a tendon in his leg, according to the source. The expectation is that surgery isn't required at this point, and that he would have been out 4-6 weeks. With the team looking to create roster space, the thinking was that they couldn't wait for Dowling to recover.

Dowling missed the Patriots' first three preseason games and much of training camp with a hamstring injury, and played in only five games in his senior season at Virginia due to multiple injuries.

The move comes one day after the release of veteran cornerback Leigh Bodden, and leaves the Patriots with Devin McCourty, Kyle Arrington, Antwaun Molden, and Phillip Adams on their 53-man roster at the position.

The 35-year old Faulk adds experience, but his role in the Patriots' backfield going forward is unclear, having not played since Week 2 of the 2010 season, when he suffered a season-ending knee injury. Faulk's role as a pass-catching back has since been filled by Danny Woodhead, while the Patriots drafted Shane Vereen (second round) and Stevan Ridley (third round) this season.

Deaderick adds depth to the Patriots' interior defensive line, which has been depleted after season-ending injuries suffered by Mike Wright and Myron Pryor. The 2010 seventh-round pick started four games for the team last season.

Meanwhile, linebacker Jerod Mayo and offensive lineman Sebastian Vollmer are with the Patriots in Pittsburgh, giving them a chance to suit up for Sunday's game against the Steelers.

Both had been listed on the injury report as questionable, and the Patriots had reported no downgrades Saturday night

Mayo, one of the team's defensive captains, sprained his MCL against the Raiders on Oct. 2 and has missed the last two games. Vollmer, the team's starting right tackle, has missed five of the team's six games with a back injury, playing only in Week 2 against the Chargers.

Safety Josh Barrett (thumb), running back BenJarvus Green-Ellis (toe) and defensive lineman Albert Haynesworth (back) were other Patriots players on the injury report. All are with the team in Pittsburgh.

With linebacker Dane Fletcher (thumb) the only player ruled out, the Patriots will have to deactivate six others 90 minutes before kickoff.

Mike Rodak is a regular contributor to ESPNBoston.com. Information from ESPNBoston.com's Mike Reiss was used in this report.