The Washington Wizards turned down a trade with the Oklahoma City Thunder for James Harden this summer because team owner Ted Leonsis was unwilling to commit to what would have been a roughly $80 million, five-year contract for the high-scoring player, according to multiple people with knowledge of the proposed deal.

The Wizards would have sent rookie guard Bradley Beal and second-year forward Chris Singleton to the Thunder in return for Harden, winner of the NBA’s sixth-man award with Oklahoma City last season, according to these individuals, who spoke on condition of anonymity because they were not authorized to talk about the proposal.

The Thunder traded Harden to the Houston Rockets in October. The Rockets, who play the Wizards in Houston Wednesday, gave Harden, who is having an all-star caliber season averaging nearly 25 points per game, the large contract he had been seeking.

Leonsis, Wizards President Ernie Grunfeld and Thunder General Manager Sam Presti all declined comment when asked about the proposed trade. One Wizards official denied that Oklahoma City had offered Harden in exchange for Beal and Singleton, stating that the Thunder was also seeking an established player — which the Wizards didn’t have — in return. “That’s not true,” the official said about the proposed deal.

Beal was drafted third overall by Washington in June, and the Thunder didn’t make the offer for Beal and Singleton until two months later, according to an NBA front office executive, who requested anonymity because of the sensitivity of the subject matter.

A person with knowledge of Oklahoma City’s interest in Beal said the Wizards’ decision to hold on to Beal made sense because teams are often willing to trade draft picks but are more inclined to keep players once they’ve been selected.

The Wizards, who before the trade proposal came up had acquired three expensive veteran players, also likely would have been subject to an NBA luxury tax penalty for having a total payroll over the prescribed threshold if they had signed Harden.

Considering how poorly this season has begun for the Wizards — who beat the New Orleans Hornets 77-70 Tuesday but still have an NBA-worst 3-15 record — and the general lack of excitement surrounding the team, dealing for Harden might have been worth the risk in the short term.

Harden was drafted third overall out of Arizona State in 2009 and came into his own last season, when he helped the Thunder reach the NBA Finals before playing onthe gold medal-winning U.S. Olympic team. The 6-foot-5 lefty ranks fifth in the NBA in scoring this season.

The Wizards would have had one of the more dynamic young back courts in the NBA, with the 22-year-old John Wall and the 23-year-old Harden. Harden also could have helped the Wizards better withstand the absence of Wall, who remains sidelined with a stress injury in his left knee, which was diagnosed in late September.

Oklahoma City traded Harden because it risked a stiff luxury tax bill once the penalties of the new collective bargaining agreement take hold in the 2013-14 season.

At the time the trade was discussed, the Wizards already had committed more than $33 million in salary this year after acquiring three veteran players — Nene, Emeka Okafor and Trevor Ariza — in an effort to bring stability to a young roster.

The Wizards also set aside money for the summer of 2014, when Wall, a former No. 1 pick, Kevin Seraphin, Jordan Crawford and Trevor Booker will become restricted free agents. Several big name talents — LeBron James, Rudy Gay, Carmelo Anthony and Chris Bosh, among others — also could enter the open market.

If the Wizards had traded for Harden, his $5.8 million salary this season would not have changed the team’s payroll much. But with the maximum deal Harden signed with Houston, his salary will jump to $13.7 million next season, when the Wizards would be committing almost $68 million in salary for just 10 players.

Even if the Wizards filled out the 15-man roster with minimum-salaried players, that would have potentially put the team’s payroll above the current luxury tax threshold of almost $70 million this season.

With the new luxury tax penalty plus another $7.8 million going to the waived Andray Blatche the Wizards’ payroll would actually be close to $90 million.

The Thunder held the 27th pick in the first round of the June draft but met with Beal beforehand and had conversations with teams in position to select him, including the Wizards, according to individuals with knowledge of the situation and published reports.

“It was weird. I met with a few teams and I was like, ‘You guys are all the way down in the draft. I’m projected to go top five.’ I was like, ‘Why are you guys interviewing me?’ It was still cool,” Beal said recently, when asked about meeting with Oklahoma City before the draft. “Sam Presti is a great guy and they showed interest. It was a great feeling for me, because that’s a team that was on the verge of winning a championship and to be part of that would’ve been tremendous. The chips fell in a different place, but I’m happy where I am right now.”

The 19-year-old Beal has had a difficult rookie campaign and has struggled with his shot but is far from a fully developed player. Singleton has moved back into the starting lineup after making 57 starts at small forward as a rookie.