Brad Stevens is taking initiative in improving the Celtics this offseason.

BOSTON (AP) — Brad Stevens knows the Celtics need to make changes this offseason if they hope to remain in the mix of what is expected to be a retooled group of teams competing at the top of the Eastern Conference next season.

Just don’t expect Boston’s president of basketball operations to blow up a roster he believes is on the cusp of finishing the job after coming within two wins of an NBA title.

“We have to walk a fine line a little bit. I think teams are fragile. I think the way that teams work together and operate together are fragile,” Stevens said Tuesday. “And I think your identity as a team, when you find one that’s successful — which we did this year on the defensive end of the floor and when we were at our best sharing the ball offensively — those things are fragile.

“So just to add (players) doesn’t mean that you’re not taking something away from the group.”

While Stevens was pleased with how the Celtics recovered from their 18-21 start to grab the East’s No. 2 seed and the conference title, he thinks their slow start has direct links to how the Golden State Warriors were able to power past them in the finals.

“When you start off 18-21, you’ve got to fight, scratch and claw to get into the playoffs, get into the seeds, get home court,” Stevens said. “You got to do all that stuff and there’s no margin for error.”

It meant less rest throughout the season and as the minutes piled up, he thinks it took a toll on the team and particularly on star Jayson Tatum, who couldn’t produce the same numbers he did in the finals as he did early in the postseason.

That said, Stevens will be looking to add another playmaker around the core group of Tatum, Jaylen Brown and Marcus Smart, while looking to continue to develop the bench with players currently on the roster.

If Boston does want add to any outside pieces, Stevens said the front office has been given the OK to spend whatever is necessary. But permission doesn’t mean he plans to exhaust what he called their “limited resources.”

The Celtics got below the luxury tax threshold just before the trade deadline this past season and don’t want to exceed it unless it’s warranted.

They own only a second-round pick (No. 53 overall) heading into Thursday night’s draft. But they also have three trade exceptions totaling just under $30 million to play with, including about $17 million left from the one created from its sign-and-trade of Evan Fournier last August.

“The big one expires in July, we’ve got a couple of others that expire later, they’re all reasonable amounts that we can take good players in with,” Stevens said. “It’s still about being prudent and thoughtful about what the deal is.”

That will be done in concert with the input coach Ime Udoka, who Stevens thinks found a rhythm his first year on the sideline following the slow start.

“In the first 40 games or so, he went through pretty much everything you can go through as a as a coach in Boston,” Stevens said. “I think that’s a testament to the way that he stayed even keel. … I’ve told people I’m close to all along, I think his ability to bounce back after the tough losses in the playoffs was really special.”

As for Stevens’ own evaluation of his first year in his new job, he said he continues to learn by the day.

“I still feel like I’ve got a long way to go in this in this role,” he said. “I’ve got great people that I lean on every day around me, and I’m thankful for that. Our front office does an amazing job. And, you know, without all their help it would be a lot more difficult, that’s for sure.”