Harrison is down and out for tonight

INDIANAPOLIS -- Safety Rodney Harrison, who returned to the practice field Thursday (and Friday) for the first time since injuring his right knee Dec. 31, was downgraded to out for tonight's AFC Championship game.

Harrison had been listed as doubtful, giving him a 25 percent chance or less of playing.

In Harrison's absence, the Patriots are once again expected to turn to James Sanders and Artrell Hawkins at safety, as that duo has started both playoff games. Hawkins is tied for the team lead among defensive backs with 11 tackles in the postseason, and Sanders has recorded 10 tackles and had his first postseason sack last Sunday in San Diego. Veteran Chad Scott has also rotated at the position, mostly on third down.

"I think those guys have done a good job," coach Bill Belichick said early last week. "Those guys work hard. They've certainly improved as they've worked together."

The Patriots did not downgrade any other players on their injury report, meaning receiver Troy Brown, nose tackle Mike Wright, and offensive tackle Ryan O'Callaghan -- all of whom are questionable with flu-like symptoms -- have not been ruled out.

Only two NFL teams were undefeated at home in the regular season -- the Chargers and Colts. The Patriots handed the Chargers their first home loss last Sunday, and now they are looking for a sweep. The Colts are 9-0 at the RCA Dome this season.

It would be a significant accomplishment for a team that has played some of its best football on the road. The Patriots are 8-1 away from home, the NFL's best mark.

"I'm not going to say we don't bond at home, but on the road there is something different when you have to bring your own energy to the game," said tight end Daniel Graham. "It is going to be a hostile environment."

As they often do before road games -- when they use a silent snap count -- the Patriots spent three days inside the Dana-Farber Field House as part of their preparations. They pumped up the music to simulate the raucous environment expected tonight.

Quarterback Tom Brady, linebacker Tedy Bruschi, running back Kevin Faulk, special teams captain Larry Izzo, left tackle Matt Light, defensive lineman Richard Seymour, Brown, and linebacker Mike Vrabel will be playing in their fourth AFC Championship game with the Patriots since Jan. 27, 2002. Long snapper Lonie Paxton has been with the team for all of the appearances, but tore his ACL and missed the 2004 contest, and this would have been running back Patrick Pass's fourth appearance, but he's on injured reserve.

"You still have to go and do it," said Seymour, the five-time Pro Bowler, when asked if that experience can make a difference.

The second time around has been kind to the Patriots. New England is 19-6 when playing a team for the second time in a season since 2000, and 7-1 when facing an opponent against whom they lost earlier in the season . . . The Patriots have won their last 10 indoor games, dating to 2001, and have scored 31 or more points in each of their last five games indoors. The last indoor game they lost was Thanksgiving Day, 2000 -- 34-9 to the Lions at the Pontiac Silverdome . . . Izzo is hoping the Patriots' special teams units can provide an edge. "Field position is huge in these sorts of games," he said. "We feel we have been improving steadily throughout the year." . . . The Patriots have allowed just three sacks in 88 pass attempts in the playoffs.

Mike Reiss can be reached at mreiss@globe.com.