GREENBURGH, N.Y. -- New York Rangers right wing Mats Zuccarello is being listed by the team as out indefinitely with an upper-body injury and is not expected to be ready to open the Eastern Conference Second Round series later this week against either the New York Islanders or Washington Capitals.

Zuccarello was hit in the left side of the head by defenseman Ryan McDonagh's slap shot late in the first period of Game 5 of the first-round series against the Pittsburgh Penguins this past Friday. He left the game with 3:58 remaining in the first period and did not return.

"It's a tough play to watch for sure," McDonagh said. "You see him take it off the head, that's a scary play."

On the plus side, defenseman Kevin Klein said he is 100 percent and ready to play in Game 1 of the second round. Klein hasn't played since March 11 because of a broken left arm.

"It's been a while," Klein said. "When you're injured you're not really around the team as much as you'd like. You watch the guys out there battling. I just want to be out there and I can't wait to be."

Rangers coach Alain Vigneault indicated Monday that right wing Martin St. Louis will move up to play with center Derick Brassard and left wing Rick Nash on the Rangers' top line if Zuccarello is unable to play.

James Sheppard is expected to take Zuccarello's spot in the lineup and will go in on the fourth line with Dominic Moore and Tanner Glass. Jesper Fast, who played on the fourth line against the Penguins, should move up to the third line with Kevin Hayes and left wing Carl Hagelin.

The line of center Derek Stepan, right wing J.T. Miller and left wing Chris Kreider is expected to remain intact.

Vigneault said the Rangers will recall a forward from Hartford of the American Hockey League prior to the second-round series starting so the team has 13 healthy forwards. Hartford is playing the Providence Bruins in the Calder Cup Playoffs, but would be eliminated with a loss Tuesday.

"We don't have an extra forward at this time," Vigneault said. "You need at least one spare at both positions if someone gets sick during the day. We can't risk that."

Sheppard has seven points in 24 career Stanley Cup Playoff games with the Minnesota Wild and San Jose Sharks. He had six points in seven games with the Sharks against the Los Angeles Kings in the Western Conference First Round last season.

The Rangers acquired Sheppard from the Sharks on March 1 for a fourth-round draft pick in 2016.

"I think sometimes guys have a plan to do more than they can do, and that's not something I'm looking to do," Sheppard said. "I'm looking to do whatever I can to contribute. I know what I can do and everyone else knows what I can do, and that's what's expected."

Klein's return likely means Matt Hunwick will join Chris Summers as the extra defensemen.

Keith Yandle did not participate in the Rangers' optional practice Monday. Vigneault said Yandle is dealing with overall soreness, but he expects him to be able to play in Game 1. Marc Staal did not skate but is expected to be good to go for Game 1.

Vigneault said he likes the lefty-righty combinations that he can use with Klein, a righty, back in the lineup. The Rangers were using two righties (Dan Girardi and Dan Boyle) and four lefties (McDonagh, Staal, Yandle and Hunwick).

"I always prefer the righty-lefty," Vigneault said. "It's easier for both breakouts and transition in the neutral zone."

Klein said he was progressing well enough last week that he likely would have been able to play against the Penguins in Game 6 had the series extended that far. He said the extra days off because the Rangers beat the Penguins in five games are beneficial to his strength training.

"I feel in good shape, have been skating a lot, and I feel strong now, which is a positive," Klein said. "I feel I can be out there 100 percent."

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