Golden State coach Steve Kerr knows that a new era of Warriors basketball is about to begin.

He just doesn't know what that means yet.

It has been a rough summer for Kerr, whose roster is wildly different following the offseason departures of Kevin Durant, Andre Iguodala, DeMarcus Cousins and Shaun Livingston — all on the heels of the team losing the NBA Finals to Toronto and Klay Thompson tearing an ACL in the last game of this past season. He spoke of the summer of tumult Monday, when USA Basketball opened its World Cup training camp.

"This summer was painful in many ways, losing the guys that we did," said Kerr, a USA Basketball assistant this summer under coach Gregg Popovich. "But reassuring, in the sense that we brought back some key guys who are going to help us kind of get to that next era, whatever that looks like."

The Warriors kept Thompson, to no surprise, after a five-year, $190 million contract got finalized quickly in free agency. Golden State also reached an agreement over the weekend to retain Draymond Green on a four-year, $100 million extension that kicks in for the 2020-21 season — a deal that is a bargain to the Warriors, especially since Green could have commanded much more had he waited until next summer.

Kerr said locking Green into a new deal has been a talking point between he and Warriors general manager Bob Myers for a long time. He wasn't surprised that Green took the deal now instead of waiting a year for a more lucrative one.

"I think every player sort of faces these moments where they've got to decide, 'Am I going to mitigate risk and sign something now or play it out?' That's up to them," Kerr said. "Obviously, everyone goes about it differently. But it didn't surprise me that Draymond signed. He wanted to be here. He's talked about it all along."

So Green, Thompson and Stephen Curry remain from the core of Golden State's three titles in the last five years. Durant, Iguodala and Livingston are key championship-team parts who are gone, and the newest Warriors standout should be D'Angelo Russell — brought in from Brooklyn, the team that now employs Durant.

Kerr said he can't wait to coach Russell, who will initially be asked to fill part of the scoring void that will be created when Thompson can't play until likely the latter portion of this coming season while he rehabs from the ACL surgery.

"He's a great young talent and I think he's going to fit right in with our group," Kerr said. "We're going to need him desperately. Without Klay, especially, we'll need D'Angelo's scoring and it's up to us as a staff to figure out how best to use him to shake the team, shake the offense. And we'll figure it out."

The other change Golden State is dealing with — besides a move from Oakland to San Francisco — will be on the expectation front.

No longer are the Warriors the overwhelming preseason favorites to win the NBA title. Some oddsmakers say Golden State is no better than the fifth-best bet just to win the West behind the Los Angeles Clippers, Los Angeles Lakers, Houston Rockets and Utah Jazz.

"I'd rather be the favorite again, to be honest with you," Kerr said. "But I like coaching. Every year's a little different. This will be a lot different. But I'm excited to coach the guys who are coming back and the many young, new players that we've got. It's a new challenge and I'm excited for it."