NEW YORK -- Already in possession of the NHL's best record, the Washington Capitals might have an even stronger lineup when they take the ice Tuesday against the New York Rangers.

The Capitals swung a deal Monday night to acquire defenseman Kevin Shattenkirk from the St. Louis Blues. According to TSN, Shattenkirk is expected to make his Washington debut Tuesday at Madison Square Garden.

Shattenkirk and goalie Pheonix Copley joined the Capitals in exchange for a 2017 first-round pick, a conditional second-round pick and forwards Zach Sanford and Brad Malone.

"We are excited to welcome Kevin to our organization," Capitals general manager Brian MacLellan said in a statement. "We felt it was important to acquire another defenseman to strengthen and add depth to our blue line. Kevin is a skilled, puck-moving defenseman who we think will help our team at even strength and on the power play."

Shattenkirk's arrival could help the Capitals thwart the Rangers' hopes of catching up in the Metropolitan Division standings.

The Rangers (40-20-2) have played one more game and have seven fewer points than the Capitals (41-13-7), who lost 2-1 in regulation at MSG on Feb. 19. The Capitals have won two of three since that setback, while the Rangers have split their four contests, practically negating any forward progress.

Playing their fifth game in eight days, the Rangers were thoroughly handled the Columbus Blue Jackets on Sunday afternoon 5-1 at MSG.

Are the Rangers getting fatigued?

"I'm not sure, but it certainly can't be an excuse," New York center Derek Stepan said. "We have played three straight overtime games. I don't know if that's the case, but whatever it may be, we just weren't the best team tonight. The better team won."

The Rangers had won six straight before this current 3-2-1 stretch. They beat the New Jersey Devils in overtime on Saturday, although they got off to a slow start in that game. They fell behind 1-0 early against Columbus, a trend that disappeared during the winning streak but it appears to be back.

"We talked about trying to have a good start here, didn't have one against Jersey and didn't have another one here tonight," Rangers captain Ryan McDonagh said. "That is disappointing for sure, but I don't think anyone should be happy with their game tonight. We've had a lot of hockey here, but that's everybody. We've had a good stretch here where things have been going our way, we've been finding ways to win, but you've got to come ready to play and come ready to put in a 60-minute effort here, and we didn't do that."

The Capitals won six in a row heading into their bye but have lost three of five since returning, including a 5-2 road loss to the Nashville Predators on Saturday night. One positive for the Capitals: In their loss to the Rangers last week, they were playing the second half of a back-to-back on the road, while this time they will have an extra day of rest before skating at MSG.

If rust isn't the issue, it could be injuries. Defensemen Matt Niskanen and Brooks Orpik and right winger T.J. Oshie have not played the past two games, although all three skated Monday in preparation for the Rangers. Niskanen appears to have the best chance of playing, though coach Barry Trotz said he wouldn't know until Tuesday who would be in his lineup.

Or maybe the downtown has to do with the recent slump of Alex Ovechkin, who was held without a shot in two of the Capitals' past six games, both losses. He had a shot and a goal taken away against the Predators after a video review showed he was offside, but Trotz isn't worried about his captain's production even if it is down now.

"Obviously, he's a shooter; he's got to get pucks to the net," Trotz said. "He's a little off, a little bit off. Players will go through that. Ovi's pretty streaky if you look in his past. It wouldn't surprise me if he got 10 goals in the next five games. It's how he operates. Sometimes, he'll go a little bit flat there, so he's just going through a little bit of a dry spell, I think."