Over the course of the 2019-2020 NBA season, Steve Kerr will face challenges as the Warriors head coach that he has never faced before. Out of the six seasons he has spent in this role, it is expected to be his most difficult by a wide margin.

This is not to say that he is yet to face any obstacles. Although he has led the Warriors to five straight NBA Finals appearances and three titles, he has also dealt with a wide variety of circumstances that come with coaching a great team. He has had to manage the egos and playing time of multiple superstars. He has had to create and sustain a winning culture within the organization. He has had to control the emotions of his players while simultaneously letting them be themselves. He has had to work closely with his assistants to determine the best course of action for on-court play in a wide variety of basketball situations.

None of those tasks have been easy by any stretch of the imagination and with the help of assistants such as Alvin Gentry, Luke Walton and Jarron Collins, he has handled all of them well. But they all pale in comparison to what is coming next.

In previous seasons, Kerr has had four All-Stars—including two league MVPs—to work with, but that doesn’t tell the full story. Those four players had styles of play that worked spectacularly well together when all four were playing their best. Two of the four are superb two-way players, another is a former Defensive Player of the Year and the fourth is one of the most impactful offensive players in NBA history. All of this added up to one of the most dominant lineups of all time, one that had tremendous room for error. There is no such situation for the upcoming season’s team.

Yes, the team still has Stephen Curry and Draymond Green. Yes, they brought in All-Star D’Angelo Russell to fill in for the injured Klay Thompson. However, there are questions throughout the roster unlike any that Kerr has had to deal with in his tenure thus far as coach.

The primary issue for Kerr, as it is for many coaches, is crafting offensive and defensive schemes based around the players he has. In the past, he has instituted an offense heavy on ball-movement and outside shooting. While that game plan will still be a part of the team’s identity, Kerr no longer has the personnel necessary to run this on the overwhelming majority of his offensive plays the way he has in the past. Instead, it appears he will need to institute an additional facet to the offense based more around pick-and-rolls, slashing and driving to the hoop. It’s something he hasn’t really made a major part of his offense before, and we will watch it succeed or fail in real time. But it’s not just offense that Kerr has to manage in a new way. It’s also the other side of the ball. This offseason, the team lost good defenders in Shaun Livingston and Kevin Durant and superb defenders in Andre Iguodala and Thompson. Though they still have their defensive anchor in Green and signed some decent defenders to make up for the ones lost, Kerr and his assistants—particularly stellar defensive coach Ron Adams—face entirely new challenges on defense. They no longer have long, positionless wings who they know can switch at will, although Kevon Looney is doing a fine imitation of that kind of player. They can no longer guarantee the crispness of their defensive rotations the way they have in the past. It will be fascinating to see if the coaches and players are up to the task of mastering new defensive strategies.

Furthermore, the player departures of this past offseason have created questions in the lineup, especially in the second unit. Kerr can no longer rely on Iguodala and Livingston, who have served as his unofficial bench captains throughout his tenure. Instead, he will have to determine anew who his sixth man and veteran bench presences will be.

On both ends of the court, the team and its head coach will be tested. But it’s not just on the court where those tests will take place.

The roster has been overhauled in a way unlike any of Kerr’s previous five seasons with the organization. This means that many of the players will have to develop chemistry together and it’s up to Kerr to help facilitate that.

Kerr’s ability to create a culture of enjoyment, selflessness and winning has been one of his greatest skills as a coach. It was on display in 2014-2015 when he helped Iguodala and David Lee accept their bench roles, as well as in 2016-2017 when he integrated Durant into the team’s already star-studded lineup. But last season, as the drama swirled surrounding Durant’s free agency, the chemistry that had driven the Warriors’ success began to break down. Most notably, a heated argument between Durant and Green during and after a November loss to the Los Angeles Clippers led to Green receiving a one-game suspension and marked the beginning of the end for Durant’s time with the Warriors. Now that the Warrior roster has an all-new look, Kerr needs to try to recapture the chemistry the team experienced at it’s most successful. While such a transformation won’t happen in a single day, Kerr has proven he can do it before. Now it’s up to him to do it again.

These are the times that will try Steve Kerr’s soul. His skill as a head coach is being tested like never before. His previous five seasons have featured some of the greatest rosters ever assembled. Now he doesn’t have that. The only thing left to do is wait and see how he handles it.