WASHINGTON — The defending Stanley Cup champion Capitals have lost top-four defenceman Michal Kempny to an injury.

Coach Todd Reirden said Friday that Kempny is out indefinitely with a lower-body injury. Kempny appeared to injure his left leg in an overtime loss to Tampa Bay on Wednesday, when he needed helped getting to the locker room.

Reirden said the 28-year-old from the Czech Republic is still undergoing tests and he didn't want to rule out Kempny for the rest of the regular season.

"I don't feel comfortable saying that until I get a little bit more medical advice on that one, and so we go through all the proper testing we need to know so we can set that proper timetable," Reirden said. "But right now, I just plan on not having him for an indefinite amount of time."

Kempny was a significant piece of the championship run last spring after being acquired ahead of the trade deadline. He has remained an important player for the Capitals this season on a pairing with All-Star John Carlson, recording six goals and 19 assists and averaging 19:11 of ice time in 71 games.

"He's a good defender, he's got great speed and a good attacker, I would say, on defence," Carlson said. "He takes away time and space really well. A guy that's really stepped it up in the offensive department too this year. We're surely going to miss him."

With Kempny out and the Capitals up against the salary cap, 24-year-old Christian Djoos goes into the lineup alongside Carlson. Djoos played on Washington's third pairing in the playoffs last year with veteran Brooks Orpik.

"He adds different dimensions of the game than say Kemps does," Carlson said. "We get to see that more now. I've played with him before. I'm looking forward to it again. I think we have depth ... I think the talent and how everyone can work together that we've proven in the past, in this year alone, guys have been out of the lineup and other people have stepped up and filled voids."

Washington is trying to finish first in the Metropolitan Division for the fourth consecutive year.

___

Follow AP Hockey Writer Stephen Whyno on Twitter at https://twitter.com/SWhyno

___

More AP NHL: https://apnews.com/NHL and https://twitter.com/AP_Sports

Stephen Whyno, The Associated Press