BOSTON (CBS) — The Bruins’ blue line is actually getting a player back.

Defenseman Charlie McAvoy has been activated from injured reserve, the team announced on Thursday. But just to keep the universe in balance, fellow defenseman Kevan Miller is heading to IR.

McAvoy missed the last 20 games with a concussion he suffered back on Oct. 18 against the Edmonton Oilers, but hit the practice ice in Boston without a “no contact” jersey earlier this week. We’ll see if he’s back on Boston’s top defensive pairing Thursday night when the B’s visit the Tampa Bay Lightning. Wherever McAvoy plays, his return will be a big boost to a defenseman corps that is still missing captain Zdeno Chara, who is sidelined with a left knee injury.

While McAvoy is set to return, Miller will not be back anytime soon after suffering a throat injury on Nov. 26 in Toronto. Though initial x-rays were negative, Miller underwent a CT scan which revealed a cartilage injury to his larynx. He won’t be re-evaluated for at least another month.

The Bruins also announced that they have claimed forward Gemel Smith off waivers from Dallas. To make room for him, defenseman Connor Clifton was assigned to Providence on Thursday.