GREENBURGH, N.Y. — It’s down to the wire. By Saturday night, after the Rangers’ regular-season finale and the Islanders’ game against the Sabres, the Blueshirts finally might learn the identity of their first-round playoff opponent, either the Pittsburgh Penguins or the Florida Panthers. The Islanders will play the other team.

The Rangers have 99 points, tying them with the Islanders, who have a game in hand. This afternoon at Madison Square Garden, the Rangers will play the Detroit Red Wings, who remain in a scramble with the Flyers and Bruins for the final two postseason berths in the Eastern Conference.

A point or two would keep the Rangers in the running for third place in the Metropolitan Division, which would match them against the second-place Penguins.

A regulation loss would inch the Blueshirts closer to a wild-card spot and a matchup with the Atlantic Division champion Panthers, because all the Islanders would need is a point Saturday night or against the Flyers on Sunday to finish third.

The Rangers’ coaching staff already has done some preliminary scouting of the Penguins and Panthers.

“We’ve started preparing for both options. Not in depth,” Vigneault said. “I’m hoping by [Saturday] we might have a decent chance of knowing. If we don’t, and it goes to Sunday, the coaches Saturday night and Sunday will be preparing for both teams. When the players get here on Monday [for practice], whoever the opponent is, the guys will be ready.”

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Some key players will be missing for the Rangers. Defensemen Ryan McDonagh (hand) and Dan Girardi (upper body) won’t dress and forwards Mats Zuccarello (lower-body injury from blocking a shot on Thursday) and Viktor Stalberg (lower body) also are sidelined.

Coach Alain Vigneault also has chosen to start backup goalie Antti Raanta against the Red Wings, presumably to avoid the chance of Henrik Lundqvist being injured before the playoffs. Lundqvist was pulled in two of his past four starts.

Rookie forward Oscar Lindberg will be in Saturday’s lineup and Marek Hrivik was summoned from Hartford on an emergency basis.

Although McDonagh remains out indefinitely and is unlikely to be ready for the start of the playoffs, Vigneault said Dan Girardi, who struck his head and neck on the boards after a check from Tampa Bay’s Brian Boyle on Tuesday, is expected to be ready. Zuccarello and Stalberg also should be able to return for Game 1 in either Pittsburgh or Florida.