The Boston Bruins are on a two-game losing streak, but they're probably losing even more on the injury front.

Goalie Tuukka Rask returned to practice Friday, as The Athletic's Fluto Shinzawa reported. But Charlie McAvoy, Brandon Carlo, Kevan Miller, John Moore and Urho Vaakanaien all remained sidelined, while captain Zdeno Chara is expected to miss four to six weeks while recovering from a left knee injury.

It remains to be seen if fellow captain Patrice Bergeron will be hampered by his own injury, an upper-body ailment suffered on a hit Friday night. But Chara's absence alone marks a significant loss for Boston's blue line, which had deployed the 41-year-old six-time All-Star as one of its most important defensemen this season.

From Shinzawa's report: "Before Chara limped off the ice, [coach Bruce] Cassidy enjoyed the security of sending out his strongman for every difficult defensive assignment. Even while McAvoy and Carlo suffered their respective injuries, Chara was the constant on Cassidy's top pairing."

The Bruins have since confirmed the report, saying Chara will be re-evaluated in a month:

Chara initially left the ice on Wednesday during the Bruins' 6-3 loss to the Colorado Avalanche. The six-time James Norris Memorial Trophy finalist collided with Avs center Carl Soderberg during the first period, and an awkward turn of the knee forced Chara out of action after just over five minutes of playing time on the night. He missed more than a week of games in 2017-18 due to an upper-body injury but has otherwise been durable over the course of his Bruins career, appearing in fewer than 70 games just twice since 2006-07.