In the midst of their worst stretch of the season, the Rangers received a lifeline.

Kaapo Kakko was activated off long-term injured reserve and is slated to return to the lineup on Sunday in the Blueshirts’ second game of back-to-back matinees against the Capitals at Madison Square Garden.

After missing 21 games with a lower-body injury, which he sustained in an awkward fall along the boards following a corner collision with Sabres defenseman Erik Johnson on Nov. 27, Kakko is coming back just in time to try and help the Rangers stop the bleeding of a season-high four-game losing streak.

“He’s healthy, he’s cleared,” head coach Peter Laviolette said of Kakko before the game. “He’s been with us for a while. It’s nice to have him back. In practice, he’s looked like he’s skating well. He’s protecting pucks. It’s his first game back after being off for a little bit, but I’m sure he’s excited to get back in there and play.”

The Finnish wing is not under any sort of restrictions or ice-time limits, according to Laviolette, who noted that he and his coaching staff were still having conversations about the lineup.

It’s likely that Anton Blidh, who made his season debut and Rangers debut on Saturday in Washington, will be scratched.

While Kakko only had two goals and one assists in 20 games before his injury, the Rangers have had two AHL call-ups in their lineup the previous five games.

The team needs a boost and Kakko is the kind of player who can provide it.

“You miss everything a little bit when it comes to Kakko,” Laviolette said. “He protects the puck really well in the offensive zone. He’s big. He’s strong. He’s young. He’s fast. He’s capable defensively, certainly capable offensively. You lose a player like that for a bit, you feel it. So it’s good to get him back out on the ice.”