Brooks Orpik, left, could return to the Capitals' lineup soon. (Pablo Martinez Monsivais/Associated Press)

Washington Capitals defenseman Matt Niskanen will not play in Monday’s matinee against the Nashville Predators, missing a second straight game with a “day-to-day” undisclosed “upper-body” injury. Blue-liner Brooks Orpik, who has missed the past 27 games with a right knee injury, has a slightly more hopeful status, considered a game-time decision for the 12:30 p.m. contest.

Both players practiced with the team Sunday, typically an encouraging sign that they’re not far from returning to the lineup. The Capitals beat the Ottawa Senators, 3-2, on Saturday night without Niskanen or Orpik — defenseman Christian Djoos is also out indefinitely after left thigh surgery this month — and Washington got goals from young blue-liners Madison Bowey and Tyler Lewington. If Orpik doesn’t play Monday, the defense duos are expected to be the same, with an all-rookie third pairing of Lewington and Jonas Siegenthaler. Bowey skated beside Dmitry Orlov on Saturday night, Niskanen’s usual spot. But considering Niskanen had been averaging more than 22 minutes per game and playing in all situations, it’s hard to truly replace him.

Niskanen’s injury was caused by an awkward crash into the boards during the third period of Thursday night’s game against the Carolina Hurricanes, and Niskanen told reporters that, while he was initially placed in the concussion protocol, he doesn’t have a concussion. He didn’t specify what the actual injury is.

“I went through the concussion protocol, mandatory, but it wasn’t my head," he said. “It’s one of those things where I tell them, ‘It’s not my head,’ but they see things and you go through the mandatory [protocol]. And it wasn’t my head. That’s really all I can tell you. ... It could have been a lot worse. It’s coming along here, making its progression, so we’ll see where that takes me over the next couple days.”

Orpik started skating two weeks ago after he had an arthroscopic procedure on his right knee last month, and Sunday was his second full-go practice with teammates. He has said that with it still early in the season and the team in good standings position, it’s been easier to be patient as he works his way back into the lineup after two months out of it.

“It’s tough, especially now with as many games as we’re playing, we’re not really having too many strenuous practices,” Orpik told reporters. “So you’ve got to do a lot of extra stuff with some of the guys after the practice. You’ve heard everybody else say it’s impossible to replicate that game speed and game action. The only way to do that is to actually get in a game. That will happen at some point.”

The Capitals plan to see how Orpik is feeling Monday morning before deciding on his availability for the game. Coach Todd Reirden will meet with reporters at 10:15 a.m. and provide an update then. If he were to play, it would almost certainly be on a third pairing beside either Lewington or Siegenthaler.

“I think if it was later in the year, it would be tougher to be patient,” Orpik said. "The younger guys have played awesome that have come up and done a really good job. So I don’t think you feel any pressure in that aspect, either, as well as those guys are playing. It’s a really good experience for those guys.

"We’ve been kind of spoiled here probably as long as I’ve been here. We haven’t had many injuries on the back end, so the younger guys have kind of been blocked from coming up. So if there ever is an injury in the playoffs, it’s good that these guys have the confidence and know they can play at this level.”