It's unclear when Paille suffered the head injury. He informed Julien and the training staff of his symptoms while the team was in Calgary, where he practiced with the team but did not play and was sent back to Boston for evaluation.
"Once he got evaluated by our trainers, it looked like concussion symptoms, so we sent him back home to get evaluated by our doctors," Julien said. "It was an unfortunate thing, a thing we found out about at the last minute, so we scrambled to get a player back, but the first thing we did was send [Paille] home and made sure he was well taken care of."
The Bruins are already without defensemen Adam McQuaid and Dougie Hamilton, both sidelined with lower-body injuries, along with forwards Chris Kelly (broken fibula) and Shawn Thornton, who is currently serving a 15-game suspension.
Also, Bruins forward Jarome Iginla suffered a left hand injury during a first-period fight with the Canucks' Ryan Kesler on Saturday night in Vancouver. Iginla did not practice with the team Monday and was sporting a brace on his left ring finger. He's scheduled to be examined by team doctors Monday afternoon.
"We're hoping it's all good and hopefully we get him back tomorrow," Julien said.
There's still no progress report on Bruins forward Loui Eriksson, who suffered a concussion -- his second in a five-week span -- on Dec. 7 at TD Garden.
"No, he hasn't even come to the rink, so that's the only thing I can give you right now, which is not a good sign," Julien said.
McQuaid, who participated in the full team practice Monday morning, has missed 14 of the past 17 games, including the past six straight thanks to injury.
"We're going to make sure he's 100 percent before we throw him in there," Julien said.
Hamilton is expected to miss at least a month.