Will John Wall’s supporting cast bring better results for the Wizards? (Kevin C. Cox/Getty Images)

Several main characters from a forgettable and wretched stretch for the Washington Wizards have been exiled in the past nine months, but team president Ernie Grunfeld isn’t certain that the lineup he assembled for the upcoming season will end the franchise’s four-year run of futility.

The additions of Nene, Emeka Okafor, Trevor Ariza, A.J. Price, Martell Webster and rookie Bradley Beal, however, have provided Grunfeld some comfort that the Wizards will display a level of professionalism and accountability that the team has been seeking since the rebuilding efforts began around John Wall more than two years ago.

“We’ve changed the environment that the team is about,” Grunfeld said Tuesday. “We’ve been able to flip this roster around. . . . The attitude of the team I think has changed, to be a hard working group, a group that’s willing to sacrifice for one another and a group that’s committed to winning and character on and off the court.”

The Wizards will begin their 10th training camp under Grunfeld’s guidance next week at George Mason University, but Nene — the midseason acquisition from Denver in a three-team deal that shipped out JaVale McGee and Nick Young — is unlikely to participate in the weeklong set of two-a-day practices. He is recovering from plantar fasciitis in his left foot.

Grunfeld acknowledged that Nene aggravated the injury — which cost him 10 games last season after he arrived in Washington — while representing Brazil during the Olympics but added that Nene should be healthy by the season opener on Oct. 30 in Cleveland.

“We’re going to be very, very cautious with him,” Grunfeld told reporters at Verizon Center. “We’re going to take it very slow with him and make sure that he’s 100 percent when we put him out there full time.”

Nene’s arrival helped ignite an encouraging late-season run in which the Wizards won 10 of 21 games, while going 7-4 in games that the 6-foot-10 center actually played. The success led Wizards owner Ted Leonsis to give Grunfeld a contract extension in April that would bring him back for two more seasons. Leonsis also raised the level of expectations shortly thereafter when he declared on draft night that he would find another lottery appearance “unacceptable.”

“I think that’s great,” Grunfeld said of Leonsis’s comment. “Everybody wants to be better and everybody wants to grow and everybody wants to compete for the playoffs. I think he also said if we don’t make the playoffs it won’t be the end of the world, but we want to see improvement. There’s no questions about that.”

For the Wizards to abandon continued residence in mediocrity, they will need Wall to take the next step. After the latest roster turnover, Wall, Trevor Booker and Kevin Seraphin are all the longest tenured Wizards after just two seasons in Washington.

Grunfeld twice stated that Wall has had “two outstanding seasons” and added that the former No. 1 overall pick has spent considerable time this offseason improving his jump shot and his physical frame.

“Because he is the No. 1 pick maybe people are expecting a little bit more out of him, but John is a competitor, he works very hard, he wants to win,” Grunfeld said. “I think he’ll show some more improvement this year.”

Grunfeld also believes that the Wizards have the talent to best accentuate Wall’s skill set. They have experienced big men in Nene and Okafor; improved perimeter shooters in Beal, Webster and Cartier Martin; a solid perimeter defender in Ariza, and Seraphin and Booker both showed improvement last season.

“I think the supporting cast is better,” Grunfeld said. “I think we’ve shown that this team is better today than it was at the beginning of last year . . . It’s a long season, a lot of things can happen, but we feel good about what we have.”