Mike D'Antoni's candidacy for the Houston Rockets' ‎coaching job is gaining momentum, according to league sources.

Sources told ESPN on Wednesday that D'Antoni has emerged as a leading candidate for the post, having impressed Rockets owner Leslie Alexander in multiple conversations since the search began. Alexander vowed to ESPN last month during the playoffs that he would take a more active role in this coaching search than he has in the past.

The Houston Chronicle on Wednesday labeled D'Antoni as the front-runner for the post. One source close to the process told ESPN that the Rockets' search had not yet progressed to that point but did say D'Antoni was indeed gaining steam in the search for a successor to Kevin McHale and interim replacement J.B. Bickerstaff.

The Rockets will be Mike D'Antoni's fifth head-coaching job after previous stints with the Nuggets, Suns, Knicks and Lakers. Soobum Im/USA TODAY Sports

ESPN reported Tuesday that Jeff Van Gundy has received strong support from Rockets general manager Daryl Morey to make a return to Houston for a second stint as Rockets coach, but sources say Alexander has yet to be sold on a reunion with the ESPN analyst, who has been working in television since the sides parted ways in May 2007.

Sources said Tuesday night that the Rockets would seek to hire a coach with strong defensive credentials, to essentially serve as D'Antoni's defensive coordinator, if talks progress to a serious stage and D'Antoni is the choice to take over.

The offensive-minded D'Antoni, currently serving as associate head coach of the Philadelphia 76ers, has previously been a head coach with Denver, Phoenix, New York and the Los Angeles Lakers.

Since its first-round elimination earlier this month, Houston has interviewed D'Antoni, former Cleveland Cavaliers coach David Blatt, former Phoenix Suns coach Jeff Hornacek, Los Angeles Clippers assistant coach Sam Cassell, Charlotte Hornets assistant Stephen Silas, San Antonio Spurs assistant coach Ettore Messina, current Rockets assistant Chris Finch and TNT analyst Kenny Smith.

It emerged Monday that Smith had been informed that he is no longer being considered for the position, with sources saying Houston is focused on hiring a seasoned former head coach. Messina, who has extensive head-coaching experience overseas, interviewed Saturday, sources told The Undefeated's Marc J. Spears.

The Chronicle reported in Tuesday's editions that former Indiana Pacers coach Frank Vogel remains "part of the process." Vogel interviewed with the Rockets in the 2011 offseason while still the Pacers' interim coach, but the job went to McHale.

ESPN reported Monday the Memphis Grizzlies have registered strong interest in Vogel, who has also interviewed for the Knicks' coaching vacancy and is widely considered a leading candidate for the Orlando Magic's coaching job along with current Magic assistant Adrian Griffin.

The Rockets fired McHale just 11 games into what was the first season of a three-year deal. Houston lost to Golden State in five games in the first round of the playoffs while slipping well off the standard it set in 2014-15, when the club won 56 games and reached the Western Conference finals.

After his own meeting with team officials, Bickerstaff withdrew from consideration early in the search, despite posting a 37-34 record upon succeeding McHale and helping Houston rally into a playoff spot after its seasonlong defensive struggles.