The blueliner suffered the injury during Saturday's game in Buffalo, when he dropped the gloves with Nicolas Deslauriers in the first period. He did not return to the game.
"I think when he fell, he hurt himself, and he came off with pain," Head Coach Claude Julien told reporters on Saturday night from the First Niagara Center.
Miller was absent from Monday's practice, as the Bruins were back on the ice at Ristuccia Arena following Sunday's off day and their three game road trip.
The Bruins skated with six defensemen at practice, and Matt Bartkowski is expected to slot into the lineup on Tuesday night against San Jose with Miller out.
"You know, we have some depth. We talk about that all the time," said Julien. "If there's an area I thought we had lots of it - we talked about it during camp, had to make our decisions who was on the back end - so here's an opportunity to take advantage of that depth we talk about."
"You never want to see it under this circumstance. Millsy's a good friend of mine. I never want to see any of these D get hurt," said Bartkowski, when asked about slotting into the lineup with Miller sidelined indefinitely. "But, like you said, it's good to get back in and play some games."
A healthy scratch during the three game road trip, Bartkowski has been itching to get back in since being on the ice for the unfortunate last-second goal by Daniel Briere in the loss to Colorado on October 13.
"Yeah, absolutely," said Bartkowski. "I mean, all-around, it wasn't a good game, but I'd like to get some games in a row here and get going."
"He's just got to play his game," said Julien. "His game is about skating and moving the puck, and where he just needs to continue to work hard on is being a little harder to play against."
While the defensive pairings always rotate during practice, Bartkowski was mostly paired with Adam McQuaid. Torey Krug moved up to be paired with Dennis Seidenberg. Both left shots, Krug spent most of the practice skating on his off side.
Griffith Back with Boston; Gagne Rotates Lines
Seth Griffith was recalled from Providence on Monday morning and was back skating with Milan Lucic and David Krejci during practice.
Griffith had been assigned to Providence following the road trip, where he was a healthy scratch in the final game against Buffalo. He helped the P-Bruins earn a 3-1 win over Portland on Sunday before rejoining Boston.
"I think anytime a player can play with some experienced players, it gives you a little bit more confidence," Julien said. "Guys are pretty good at helping guys through [it], and giving them the opportunity to get accustomed to our team, to get Seth accustomed to his line, so it certainly helps and I think that's what Seth has been doing right now, trying to soak up as much as he can."
For Saturday's game, Griffith was a healthy scratch and Matt Fraser slotted into the lineup on the fourth line. Simon Gagne skated up in the right wing spot with Lucic and Krejci. Gagne has been rotating back and forth during games, skating on Krejci's line and also on the fourth line with Daniel Paille and Gregory Campbell.
"He was OK," Julien said of Gagne's time with Lucic and Krejci in Saturday's game. "I think you know, what you saw today [during practice] is probably what you've been seeing along - a little bit of moving around."
"He can play on that line [with Lucic and Krejci], he can play on the fourth line. I think he's made our fourth line a pretty good line."
"But if Seth is going to play, he needs to play on one of those lines right now, and I think if he's to gain some experience, it's with [Lucic and Krejci]. We can alternate Simon in those positions, so that's what we've been doing so far."
Building Off Road Trip
The Bruins started to regain their identity of being tough to play against during their road trip through Detroit, Montreal and Buffalo that saw them snap a three game losing streak.
Ending with a 2-1-0 record, thanks to a 2-1 shootout win over the Red Wings and a 4-0 shutout of the Sabres, the Black and Gold came back to Boston with a lot more confidence in their game. Even the 6-4 loss to Montreal had its positives, with the Bruins starting to put goals on the board.
"Our three games on this road trip weren't bad games. I think if we had one thing we wanted to improve on, it's the defensive part of our game in Montreal," Julien said. "But the effort was there for the most part and you can see things starting to come around. So we've just got to stay on top of our game here and keep improving."
The Bruins host the San Jose Sharks and New York Islanders at TD Garden this week, before playing the Leafs in Toronto on Saturday.
"We got off to a little bit of a rough start, and we need to build our way back from it," said Reilly Smith. "Any road trip where you're coming back above .500 is a solid road trip and you try to take any positive you can from it. We have an important game [on Tuesday] and we need to try to build some momentum at home."
Practice Lineup 10/20
Milan Lucic - David Krejci - Seth Griffith
Brad Marchand - Patrice Bergeron - Reilly Smith
Chris Kelly - Carl Soderberg - Loui Eriksson
Daniel Paille - Gregory Campbell - Simon Gagne/Matt Fraser
Zdeno Chara - Dougie Hamilton
Dennis Seidenberg - Torey Krug
Matt Bartkowski - Adam McQuaid
Goalies: Tuukka Rask, Niklas Svedberg