Suns president Steve Kerr told ESPN.com that he flew in and out of Detroit on Thursday to meet with Porter, his former teammate for two seasons in San Antonio.
Porter, who posted a 71-92 record in a two-season stint as Milwaukee's head coach from 2003-05, is believed to the first to formally meet with the Suns.
Other candidates who have been mentioned prominently are Suns assistant general manager Vinny Del Negro, part-time Utah Jazz coach Jeff Hornacek, ESPN analyst Mark Jackson, Los Angeles Lakers assistant coach Kurt Rambis, three-time NBA head coach Paul Silas, Boston Celtics assistant coach Tom Thibodeau.
Jackson was to interview with the Suns on Friday, ESPN confirmed.
The Rockets have given permission to Phoenix to interview assistant coach Elston Turner, who will interview sometime next week, the Suns confirmed Friday.
"I'm excited," Turner said, according to the Houston Chronicle. "I'm looking forward to it, very much looking forward to talking about it and seeing if I'm the kind of guy they're looking for."
Porter had not surfaced in speculation before Thursday, suggesting that -- as Kerr warned recently in an interview with The Arizona Republic -- the early guesses in circulation about the Suns' pecking order are just that.
"I don't think anybody has a clue," Kerr told the newspaper. "I have my list."
Kerr has also made it clear that he plans to be "thorough and methodical" and might need "a month" to settle on a replacement for new Knicks coach Mike D'Antoni.
"There's not a huge rush because we're not one of five or six teams out there looking for someone," Kerr said. "So we don't feel like we're competing with other people."
Yet Kerr has never hidden his fondness for Porter, calling him "one of the best people I've ever met in the league" in a 2003 column Kerr wrote for Yahoo! Sports.
This is Porter's second season as an assistant to Flip Saunders in Detroit. He spent one season as an assistant to Rick Adelman in Sacramento in 2002-03 before landing the Milwaukee job, taking the Bucks to the playoffs in his first season (41-41) before a 30-52 mark in 2004-05 resulted in his dismissal.
In an interview in Thursday's editions of The Chicago Tribune, Kerr said: "What's interesting is that there are no obvious candidates now. It's not like there are really prominent former head coaches out there. Once D'Antoni was off the market, it kind of changed things."
Marc Stein is the senior NBA writer for ESPN.com. To e-mail him, click here.