Months of discord centering on elements of treatment, rehabilitation and timetables for return from a right quadriceps injury have had a chilling impact on San Antonio Spurs star Kawhi Leonard's relationship with the franchise and coaching staff, league sources told ESPN.

Under president and coach Gregg Popovich and general manager RC Buford, the Spurs have a two-decades-long history of strong relationships with star players, but multiple sources describe Leonard and his camp as "distant" and "disconnected" from the organization.

Beyond the current rehab for the injury that has caused Leonard, an All-NBA forward, to miss most of the regular season, there is work to be done to repair what has been until now a successful partnership.

In an interview with ESPN, Buford rejected the reporting of turbulence between the franchise and Leonard.

Kawhi Leonard will not make his targeted return from injury on Thursday. Soobum Im-USA TODAY Sports

"There is no issue between the Spurs organization and Kawhi," Buford said. "From Day 1 all parties have worked together to find the best solutions to his injury."

Buford described a frustrating process of rehabilitation for what has been an elusive solution to an injury.

"This has been difficult for everyone," Buford told ESPN. "It's been difficult for Kawhi. He's an elite-level player. It's been difficult for the team, because they want to play with a great teammate. And it's been difficult for our staff. Historically we've been able to successfully manage injuries. This rehab hasn't been simple, and it hasn't gone in a linear fashion."

Leonard missed the first 27 regular-season games and has played only nine. Last week the Spurs sent him back to San Antonio to continue his rehabilitation process. Leonard has told the Spurs at different stages of the process that he wasn't comfortable with his ability to play through the injury and that the Spurs shut him down.

"We sought outside expertise with the best tendon experts in the world," Buford said. "It worked beautifully for Tony [Parker], but it hasn't worked the same for Kawhi."

The 15th overall pick in the 2011 draft, Leonard has developed into one of the most dominant players in the league, becoming a two-time first-team All-NBA player, a two-time NBA Defensive Player of the Year and the 2014 NBA Finals MVP in the Spurs' victory over the Miami Heat.

Despite Leonard's absence and limited minutes in the nine games he has played, the Spurs are 30-18 and tied with the Minnesota Timberwolves for the No. 3 seed in the Western Conference.

The Spurs initially disclosed Leonard's injury on Sept. 30, announcing that he would miss the entire preseason because of right quadriceps tendinopathy. Popovich said at the time Leonard would "probably miss the beginning of the preseason or a good deal of preseason," and indicated the quadriceps issue first developed sometime in the 2016-17 season.

After Leonard missed the Spurs' first 10 regular-season games in October and November, Popovich said that he was "just coming along more slowly" than expected in his rehabilitation.

On Nov. 22, Popovich said that he had "never" encountered a quadriceps issue like the one Leonard is experiencing.

"What's really strange is that Tony Parker has the same injury, but even worse," Popovich told reporters. Parker ruptured a left quadriceps tendon in the Western Conference playoffs in May, a far more severe injury, and returned to the Spurs' lineup nearly seven months later.

Leonard made his season debut on Dec. 12, scoring 13 points in 16 minutes against the Dallas Mavericks. The Spurs kept Leonard on a minutes restriction and held him out of back-to-back games until Leonard sustained a strained left shoulder on Jan. 5 against the Phoenix Suns.

Leonard missed three games with the shoulder injury, then returned to the lineup on Jan. 13 against Denver, scoring 19 points in 28 minutes. Days later, the Spurs made public a decision to shut down Leonard indefinitely, sending him back to San Antonio from a team trip through the Northeast.

Popovich said that Leonard "didn't reinjure" the quad and insisted that the organization was erring on the side of caution with its franchise player.

"You've got to be confident in your body to go out there and play at the level he's expected to play," Popovich told reporters. "We didn't feel he was ready. His confidence level wasn't there. So we decided to give it some more time."

In 39 games without Leonard on the floor this season, the Spurs have registered a 25-14 record (5-4 with Leonard in the lineup) and ranked No. 16 in offensive and No. 2 in defensive efficiency.

ESPN's Zach Lowe contributed to this report.