BOSTON (CBS) — The Patriots lost their game on Sunday, and they also lost a linebacker.

Brandon Copeland will miss the remainder of the season due to a torn pectoral muscle, according to Pro Football Talk’s Mike Florio.

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Copeland, 29, joined the Patriots during the offseason as a free agent, after playing two years with the Jets and two years with the Lions. He played in six games, starting four, and recorded 12 total tackles — six solo and six assists.

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Copeland returned to a defensive role in Sunday’s loss to the 49ers, taking 11 snaps on D. That came after Copeland logged zero defensive snaps at Kansas City and against the Broncos. (He was on the field for 91 percent of the team’s special teams snaps in those games.) Copeland’s heaviest action came in Week 2, when he took 30 defensive snaps in Seattle.