Safety Rodney Harrison suffered his second significant injury in two years, breaking his scapula in Sunday night's game against the Colts, according to a league source.
The injury to the shoulder blade won't require surgery, although a timetable for Harrison's return is unknown.
Harrison, who turns 34 in December, suffered a similar injury in 1999 when he played for the San Diego Chargers, and he missed eight games that season.
The hard-hitting Harrison was injured on the Colts' third offensive play Sunday night, a 44-yard pass over the middle from Peyton Manning to Marvin Harrison in which the safety landed on his right side after making the tackle. He was playing in his eighth regular-season game since returning from a major knee injury in 2005 in which he tore three ligaments.
Last October, Harrison -- before undergoing surgery on his left knee -- reflected on his 1999 scapula injury in a conference call with reporters.
"It was a pretty significant injury," Harrison said, explaining the injury as a hairline fracture. "Aside from this [knee] injury, that was probably the most painful, probably the most uncomfortable injury I've had. I remember I couldn't sleep at night, couldn't lay down. I had to constantly call doctors in San Diego at three o'clock in the morning to come over and give me pain medicine.
"It was probably the most painful injury that I've had, probably even including this one. I probably sat out 8-10 weeks or something like that. It was pretty devastating."
That year, the Chargers jumped out to a 4-1 start as Harrison led the team in tackles through five games. Following Harrison's injury, the Chargers lost their next six.
Harrison was playing at a high level this season, having been credited by Patriots coaches with 42 tackles (33 solo), two sacks, one interception, and one forced fumble. In addition to providing a physical presence to the defense, the 13-year veteran also was a key cog in the communication between the defensive backs.
Harrison is the NFL's all-time leader in sacks by a defensive back (28 1/2) dating back to when sacks became an official statistic in 1982. He also has 32 career interceptions, making him the only player in NFL history to have more than 25 career sacks and at least 30 career interceptions. Harrison recently said one of his personal goals was to total 30 sacks to go with his 32 interceptions.
In Harrison's absence Sunday night, the Patriots moved veteran cornerback Chad Scott to safety alongside Artrell Hawkins, then inserted Ellis Hobbs at cornerback.
"He is a good player. Obviously, we didn't expect to lose him in the first couple plays of the game," Hawkins said of Harrison late Sunday night. "It was a big blow when he was out, but we have to make the adjustment and be professionals about it and make the plays we need to make."
The team's other opening day starter at safety, Eugene Wilson, has been sidelined four of the last five games with a hamstring injury.
The Patriots claimed third-year veteran Rashad Baker off waivers from the Vikings yesterday, adding another player to the safety mix. The 24-year-old Baker has played in 29 career games, with three starts for the Bills (2003-04) and Vikings (2005).
In addition to the 5-foot-10-inch, 198-pound Baker, the Patriots also have rookie Willie Andrews and second-year player James Sanders at the position. Veteran linebacker Don Davis has also played safety in emergency situations.
After having their defensive backfield ravaged by injuries the last two years, the Patriots stocked up on safeties and cornerbacks heading into training camp, but had three players -- Tebucky Jones, Mel Mitchell, and Randall Gay -- wind up on injured reserve.