Hurricanes general manager Don Waddell, who on June 25 said the Hurricanes can and would match any offer sheet made to Aho, said they met with his representatives at the 2019 NHL Draft in Vancouver on June 21-22 about a new contract but nothing was settled.
"It's certainly a surprise, it's a surprise it wasn't more," Waddell said Monday. "Literally we got the email at 2:40 today, so all people are not fully aware yet.
"I know my summer just got better, because I'm not going to be negotiating a contract all summer. We make a decision and move on."
Compensation to the team losing a player to an offer sheet escalates from no compensation for a contract worth $1.4 million or less per season, to four first-round draft picks for a contract worth more than $10.5 million per season.
The last offer sheet to be given to an NHL player was to Colorado Avalanche center Ryan O'Reilly, by the Calgary Flames, on Feb. 28, 2013. Colorado matched it and kept O'Reilly.
The last offer sheet to lead to a player changing teams was one given to Anaheim Ducks forward Dustin Penner, who signed with the Edmonton Oilers on July 26, 2007. Anaheim received three picks in the 2008 NHL Draft as compensation.
This is the ninth offer sheet given since 1998.
"We looked at a lot of scenarios," Bergevin said. "When you make an offer like this, you see a position that is a bit vulnerable, and we identified this team, and the player too. He's a player that we love and the offer, with the compensation, with the group of young players we have, with the contracts that are coming up in the future, we realized that this was the best place for us to be, with the best chance of getting the player."
Knowing what the cost is to keep Aho, it could provide the Hurricanes a chance to sign defenseman Justin Faulk to a contract extension.
"We are in a position that we can and would match any offer (to Aho) that was made to us. We've made that real clear," Waddell said. "There are lots of things I have to worry about in this job, but that's not one I even put one second of thought into."
Aho led the Hurricanes with 83 points (30 goals, 53 assists) in 82 regular-season games and had 12 points (five goals, seven assists) in 15 Stanley Cup Playoff games, helping them advance to the Eastern Conference Final, where they were swept by the Boston Bruins.
Selected by the Hurricanes in the second round (No. 35) in the 2015 NHL Draft, Aho has 197 points (83 goals, 114 assists) in 242 games.
"He's a player who has the potential to be a No. 1 center," Bergevin said. "We saw what he did for Carolina not only in the regular season but also in the (Stanley Cup Playoffs). He is really young and I think he is a good fit with the group of young players that we have coming up in our organization."
NHL.com correspondent Kurt Dusterberg contributed to this report