Updated

Jason Arnott has been a tremendous addition to the Washington Capitals, but according to a report by Capitals web reporter Mike Vogel, the team will be without him when it starts a six-game road trip against the Montreal Canadiens on Tuesday (7 p.m. ET, TSN).

Arnott, who has played a major role in the Caps' eight-game win streak that has pushed them to the top of the Southeast Division, is listed as week-to-week with an undisclosed injury.

The Capitals haven't lost since acquiring Arnott from the New Jersey Devils on Feb. 28, and a win combined with a regulation loss by the Philadelphia Flyers would put Washington atop the Eastern Conference.

Arnott has 2 goals and 3 assists in seven games with Washington while providing a much-needed presence in the middle of the team's second line.

"Jason has solidified that line so much," said Capitals right wing Mike Knuble after Sunday's 4-3 overtime win against Chicago. "His presence on the ice, he's always been such a smart player. It seems like he's not moving a lot, but you can't get the puck from him. He just makes simple, easy plays. His presence has been huge for us as a second center. Defensively, he's just another big body to counteract other team's one-two punches."

As Arnott goes out, however, the Capitals could be getting another center back in the lineup, as Nicklas Backstrom, who has sat out the last three games with a thumb injury, made the trip to Montreal. If he's healthy, he could replace Marcus Johansson on the top line between Alex Ovechkin and Knuble, with Johansson sliding into Arnott's spot on the second line.

Two other injured Capitals players also made the road trip -- goaltender Semyon Varlamov and defenseman Tom Poti. Varlamov last played Feb. 20 due to a knee injury, while Poti has been out since Jan. 12 with a groin injury.