The ink was barely dry on his contract when Ryan Donato played his first professional game.

Three days after his junior season at Harvard ended, Donato joined the Boston Bruins' lineup in the middle of a playoff chase in a top-six role with a spot on the power play.

No pressure, kid.

"I definitely had to learn quickly," Donato said. "Every game is important, so it had to click right away. I really didn't have a choice."

Such is the task for Donato and a handful of other young prospects joining contenders in the eleventh hour of the NHL season. It has become common for teams with no postseason hopes to sign players out of school and play them late in the regular season like Vancouver did with Brock Boeser and Arizona with Clayton Keller a year ago.

This season, some top teams are taking the chance, too.

Just as the Bruins added Donato, Minnesota signed Jordan Greenway after his season at Boston University, Anaheim signed Troy Terry after the University of Denver was out of the NCAA Tournament and Nashville brought over Eeli Tolvanen from Europe after a full year in the Kontinental Hockey League — young talent added for the playoffs without the teams giving up anything, though coaches must now integrate a new player late in the season.

"It's tough if the kids aren't good," Wild coach Bruce Boudreau said. "With our team right now in the midst of this race, every little defensive situation has got to be done right."

Every shift is magnified this time of year, adding to the burden of trying to learn a team's system. Donato, Greenway and Terry went right from college to the NHL, and Tolvanen had to adjust on the fly from the wider, European ice as Nashville tries to shore up home ice throughout the playoffs.

"It's kind of tough to come in the middle of the season and just jump in and you don't know all the guys," Tolvanen said. "You have to do it at some point, so I think it's a pretty good spot that I came a couple games before the playoffs."

Tolvanen benefited from two rounds of KHL playoffs with Jokerit and carried that intensity across the pond, while Terry and Greenway got a taste of playoff action in the NCAA Tournament. Donato's season playing for his dad and former NHL forward Ted ended, and he suddenly had to ramp things up to carry a big load for Boston amid injuries to Rick Nash and others.

Donato knew he couldn't take a shift or a game off and has stepped up with seven points in his first nine games. Coach Bruce Cassidy wasn't worried about getting the soon-to-be 22-year-old up to speed as much as seeing if Donato could handle the size, speed and pace of the NHL.

"Most of these kids that come in are offensive-minded guys, so are they going to be able to make their plays and handle a man's game?" Cassidy said. "And he's shown he's able to do that."

Donato certainly had a body of work coming in, including leading the United States and tying for the tournament lead with five goals at the Olympics without NHL players. The other three young, late-season additions — all of whom also stood out at the Olympics — are being eased in.

"We didn't really do anything at the trade deadline because we knew that we were going to get Jordan Greenway," Boudreau said. "He's gone through the Olympics and the world juniors all in the last year, so he knows what a little bit of pressure is all about. Playing at BU, he's always (on) one of the better teams playing in important games. We pretty well thought he could handle all this."

Nashville is betting Tolvanen can handle it, too. The impressive Finnish winger set a KHL record with 36 points as an 18-year-old and looked increasingly more comfortable in his first three games for the Predators, who have their sights set on a return trip to the Stanley Cup Final.

"It's important for him to see ice time before the playoffs," coach Peter Laviolette said. "The playoffs are a long haul. I think we learned that last year that you need a lot of people and a lot of parts and it's important to get him involved in the game, with the team, in the systems."

Predators general manager David Poile recalled making one trade too many at a previous deadline and messing with his team's chemistry.

"You have to be careful on both sides because you don't want to put a young player in a position to fail," Poile said. "You want to put him in a position to succeed. You also are very respectful of the players that have been with you all season long. It's also OK to have depth but you don't want to move everybody's cheese too much."

In Boston, it helps that Donato is filling a spot vacated by injuries and showing immediately he belongs. In Nashville, Tolvanen's reputation preceded him for anyone who saw what he did as one of the leading scorers at the Olympics.

"It's a special situation when somebody comes in this late and joins the team and under different circumstances, but it's been great," starting goaltender and fellow Finn Pekka Rinne said. "Certainly it adds a new, special element to our team. I think it's going to be beneficial down the road."

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Follow Hockey Writer Stephen Whyno on Twitter at https://twitter.com/SWhyno

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