BOSTON (CBS) — Tom Brady and the New England offense will still have to worry about Khalil Mack on Sunday, but the matchup may not be as daunting as previously anticipated.

Mack has been a game-changer since arriving in Chicago, making the Bears defense one of the most feared units in the NFL. Mack has been a force all by himself, racking up five sacks, four forced fumbles, an interception and a touchdown in his first five games since being acquired from the Oakland Raiders.

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But he likely won’t be at full speed when the Bears host the Patriots on Sunday, thanks to an ankle injury he suffered in the first half of Sunday’s loss to the Miami Dolphins. Mack did return and ended up playing 79 percent of Chicago’s snaps on Sunday, but finished his day without a sack for the first time in his Bears career. He’ll undergo further tests this week and is expected to play Sunday, but may not be the dominant force he’s been the first month of the season.

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That’s great news for Brady and company, though the Patriots have done a solid job keeping their 41-year-old quarterback standing upright this season. Brady has been sacked eight times in the first six games, and just twice over the last three games.

The Chicago defense has allowed just 19.2 points per game over the first six weeks, the fourth-lowest in the NFL, with their 19 sacks tied for the fifth-most. But if Mack isn’t himself on Sunday, the Bears defense will have their hands full with a Patriots offense that has rounded into shape over the last three weeks.

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Tune in to Patriots-Bears on WBZ-TV — the home of the New England Patriots. Kickoff is set for 1 p.m. with Patriots 5th Quarter on myTV38 after the game!