"He's a tough guy to replace. I've said that all along," Sullivan said. "He's really made our team a better team. He's a mobile guy. He can move the puck. He's got real good offensive instincts. He's a real, solid, two-way defenseman and it's hard to replace those guys, but we've done it all year and we'll do it again. We're fortunate we have the people that we have that we can plug in that can get the job done and we feel confident in the group that we have."
Sullivan would not confirm that Maatta will be the one to replace Daley on Sunday. Maatta has been a healthy scratch the past three games after struggling in Game 1 against the Lightning.
"I know I can play better," Maatta said. "I don't think there's big changes you can do."
Sullivan said if Maatta plays, he wants him, "just to keep his game simple, to relax and have fun and play."
"Olli's been a big part of this team for a long time," Sullivan said. "He's been a top four defenseman for this team all season long. He's done a terrific job for us and when he keeps his game simple, I think that's when he's at his best."
Re-entering the best-of-7 series with it tied 2-2 will be a challenge for Maatta, 21, who didn't want to see anyone get injured, but is eager to get back in the lineup.
"All the time you've just got to be ready to go," Maatta said. "It doesn't matter what happens. You just have to be ready to play every game. This has to be your mindset."
Sullivan said these moments prove the importance of having depth during the long playoff grind.
"I told these guys at the start of the playoffs that we're going to need everybody," Sullivan said. "If we're going to get to our ultimate goal, we're going to need everybody both in and out of the lineup in order to accomplish this. So, everybody's got to work every day to keep their games at the highest level they can possibly keep it, so that when they're tapped on the shoulder they're ready to help this team win. So, that's how strongly we feel about this group."