The deal, signed Saturday, puts Bethel under contract through the 2018 season.
The 25-year-old Bethel made the Pro Bowl as a special teams player the last two seasons. He is to start at cornerback for the injured Jerraud Powers in Sunday's game at St. Louis.
A sixth-round draft pick out of Presbyterian in 2012, Bethel has not missed a game since coming to the NFL, appearing in all 59 contests. He has 63 special teams tackles, another 14 tackles on defense, and has blocked three field goals. He got his first career interception earlier this season.
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