Speaking between sessions of a rookie camp, DeBoer said the loss of the 30-year-old Kovalchuk leaves big holes on the team's top line and specialty teams, and it will create playing time others will have to fill.
"We have to. That's the bottom line," DeBoer said Monday. "There's no, 'What can you do?' We're going to have to find a way. That's going to be the mantra. The league is not going to stand still. I think I've used that phrase before.
"No one is going to feel sorry for you, the New Jersey Devils. When the puck drops in October, we've got to be ready to compete with the guys we've got, and we've got a good group of people here."
The Devils reached the Stanley Cup finals in 2012 with Kovalchuk playing a major role, but they missed the post-season this year when they struggled in the second half of the lockout-shortened, 48-game season.
The future doesn't look bright without Kovalchuk, who walked away with $77 million left on the 15-year contract he signed in 2010. His defection comes a year after Zach Parise signed with Minnesota as a free agent.
"Sure it's different," said DeBoer, who said he needed a day to catch his breath after Kovalchuk's retirement from the NHL was announced on Thursday. "You take out a Parise, you take out a Kovalchuk, those are players that singlehandedly can do some things that only a handful of players in the world can do. So we're going to have to be a different team and have to play more of a team game."
DeBoer knew during the season that Kovalchuk was interested in returning to Russia, but he didn't expect a final decision last week. While obviously disappointed, the coach wasn't angry with Kovalchuk for leaving the team without its best player.
"I don't feel that way," DeBoer said. "Maybe I should, but I don't. I enjoyed working with him. He was a good pro. He was a good teammate in the dressing room and he'll be missed. That's my feelings on it. I don't go any deeper than that. Everybody has a personal life and personal decisions regarding their careers, and it's not my place to be stepping into those."
DeBoer maintained Kovalchuk never played last season like someone who didn't want to be with the Devils or in the NHL. He scored 11 goals in 37 games.
The Devils have been active in recent weeks, signing forward Ryane Clowe and Michael Ryder, re-signing veteran forward Patrik Elias, and acquiring goalie Cory Schneider in a draft-day trade with Vancouver.
"I know as a staff we're excited about the group we've got coming back. We're excited about the free agents we've signed," DeBoer said. "We have a lot to prove and there's going to be a lot of doubters out there. I think we're all prepared for that and are excited about the opportunity of proving people wrong."
The problem is that none of the new players or any of the remaining ones is a star like Kovalchuk, who agreed to a four-year contract with SKA St. Petersburg of the KHL on Monday.
NHL teams without stars usually don't win a lot of games.
"Like I said, it doesn't change anything here," DeBoer said. "You guys know the expectations. You know my boss. There is no taking your foot off the gas because some of these things happen.
"I mean this organization has dealt with this type of thing for the last decade, you know, back to (Brian) Rafalski and (Scott) Niedermayer and on and on. You have got to find a way."
The Devils have won three Stanley Cup titles, but none since 2003.