FOXBOROUGH, Mass. – Footballs fly at the New England defensive backs. It’s only practice, but they spend plenty of time sharpening their catching skills.

It’s time very well spent.

Led by rookie Devin McCourty with six interceptions, the Patriots are tied for the AFC lead with 18 and already have matched the team’s total for all of last season.

“We constantly work on that,” said safety James Sanders, whose interception of Peyton Manning 6 yards in front of New England’s end zone preserved a 31-28 win over the Indianapolis Colts. “If we’re not practicing on it with the Jugs machines, we’re throwing the ball constantly to each other.”

Some interceptions are easier than others, such as when Mark Sanchez thought Santonio Holmes was open last Monday night only to have Sanders glide into the path of the ball for an easy catch, one of many New York Jets mistakes in their 45-3 loss.

“When you disguise well,” Sanders said Thursday, “you don’t have to worry about working too hard to get certain plays.”

The Patriots (10-2) lead the AFC East, but they don’t expect it to be easy on Sunday, not against quarterback Jay Cutler and the NFC North-leading Chicago Bears (9-3).

Cutler is in the midst of his best stretch. The Bears are 5-0 since their bye week, with Cutler throwing just three interceptions in those games and none in his last two. His speed and ability to run toward the sideline and throw are major concerns.

“You never want to let quarterbacks get outside the pocket. Things just start going haywire at that point,” safety Jarrad Page said. “Everybody has to cover their men a lot longer (and) offenses start to hit big plays down the field, no matter who the quarterback is.”

The Patriots have interceptions against some of the best this year: Philip Rivers, Ben Roethslisberger and Manning.

That’s pretty impressive considering how young the starting secondary is. Safety Brandon Meriweather is in his fourth season and safety Patrick Chung and cornerback Kyle Arrington are in their second.

“When you get opportunities, make sure you catch the ball,” Sanders said.

In the last game, McCourty shadowed Braylon Edwards step for step along the right sideline. He looked up at precisely the right moment and made an acrobatic catch at the Patriots’ 6-yard line.

“We are trying to go after the ball every week in practice,” said McCourty, who is just one interception behind NFL leader Asante Samuel of Philadelphia. “Each week we have done a certain drill where it showed up in the game.”

McCourty’s interception of Brett Favre set up a touchdown that opened up a close game as New England took a 21-10 lead and won, 28-18.

Coach Bill Belichick has raved all season about McCourty. On film before the draft, Belichick was impressed with McCourty’s ability to analyze what he saw, so Belichick took him with the 27th pick.

“He’s really intelligent, works hard. You would think he’s a five-year veteran,” Sanders said. “He’s a real intelligent guy. He picks up a lot of subtle things on film.”

And he doesn’t care what opponents say about him. Before the win over the Jets, Holmes advised the Patriots not to have a rookie cover him.

“I wouldn’t do it if I was them,” he said.

After the rout, McCourty said: “He said something about me in the paper. I’m not worried about that. You have to come out and play.”

Another rookie, linebacker Brandon Spikes, also intercepted a pass by Sanchez after the Jets had moved all the way to the Patriots’ 9-yard line. Credit defensive line coach Pepper Johnson with an assist.

“Pepper throws balls at all of those guys every week, fires it in there and makes them catch the ball,” Belichick said. “It was kind of like the be-on-the-line drill that the linebackers do with Pepper every Friday. So, it was a nice catch.”

Cutler has a strong arm and receivers Johnny Knox and Devin Hester are extremely fast.

“They have speed all around Cutler, definitely,” Page said. “We’ve seen him outrun cornerbacks trying to get to the edge and making plays.”

If the Patriots can keep Cutler in the pocket, they should have a better chance of adding to their interception total.