New England's coach could start Sunday night without three of them. Safety Rodney Harrison is out for the season and starting cornerback Ellis Hobbs and backup Lewis Sanders were sidelined during practice Wednesday.
It may be time for rookies Terrence Wheatley and Jonathan Wilhite to step up against Manning, still dangerous despite a subpar season for him and Indianapolis.
"Even if you're not a starter, you've still got to be ready to go," said Wheatley, a second-round draft pick from Colorado.
Wheatley had his most playing time as a pro in last Sunday's 23-16 win over the St. Louis Rams. Starting cornerback Deltha O'Neal missed most of the game with a head injury and cornerbacks Hobbs and Mike Richardson were knocked out of action in the fourth quarter.
And Harrison missed his first game with a season-ending thigh injury, replaced by second-year pro Brandon Meriweather in the starting lineup.
"We were just taking names there in the fourth quarter, seeing who was available and who we could put in and 'if he went there someone else would go here' and 'he knows this' and 'he can do that,' said Belichick.
"It was definitely a scramble. But those things happen from time to time and that's why in training camp you play guys at different spots and make them learn different positions."
O'Neal came back in time to make a victory-sealing interception with 1:08 left, less than seven minutes after Hobbs left after hurting his shoulder when he broke up a pass and landed hard.
He said Wednesday the shoulder felt "fine," but he was one of four players who missed practice.
Meanwhile, the fourth-year pro has some advice for the rookies who may replace him Sunday night.
"Expect everything," Hobbs said. "Prepare yourself as much as you can. And even when you think you've prepared yourself enough, like you think you have a route covered, you never have a route covered tight enough where Peyton can make that comeback throw, he can make the deep ball, he can fit it into tight coverage."
With Harrison out, 24-year-old James Sanders is the Patriots' top safety. He feels Manning has the smarts and skills to outplay even a veteran secondary.
On Sunday, Manning may try to pick on Wheatley and Wilhite.
"Just thank God that they played against Tom (Brady) in training camp," James Sanders said, "because those are arguably one and two in this league (at quarterback). So for them to experience him in training camp, I think that's going to help a great deal."
The change in the secondary began after last season when Pro Bowl cornerback Asante Samuel left as a free agent for the Philadelphia Eagles. The Patriots signed veteran free agent cornerbacks Fernando Bryant and Jason Webster, then released both and added O'Neal, a two-time Pro Bowler, six days before the Sept. 7 opener against Kansas City after he was cut by Cincinnati.
He gave up two long completions in a 30-10 loss to San Diego, then played better the past two games, both wins.
But the Patriots are ranked 15th in passing yards allowed after finishing sixth last year. Sanders said it's difficult not seeing Harrison on the field.
"It's tough," he said, "but like Rodney said, we've played without him before and we've got to move on. We know we had success with him. We can have success without him."
"Rodney's a tough guy for them to replace," Clark said. "He brought so much to their defense, so much versatility and just that toughness that the defense always shows. So I think he allowed them to do a lot of different things.
"But they have great leadership on their defense. They're just rallying around each other and helping the younger guys out and they're definitely not going to use that as an excuse for anything."
Copyright 2008 by The Associated Press