Story highlights "Billie Joe's well-being is our main concern," bass player Mike Dirnt says

Armstrong, who sought treatment in September, "is doing well," Dirnt says

2012 club dates are canceled, while next year's shows are postponed

Green Day's "Tre!" album release is moved up to December 11

Green Day canceled the rest of its North American club tour dates for this year and has postponed all January and February shows to give lead singer Billie Joe Armstrong more time to deal with substance abuse issues , the rock band said Monday.

"Obviously the timing for this isn't ideal, but Billie Joe's well-being is our main concern," bass player Mike Dirnt said.

Armstrong, who sought treatment for substance abuse two days after his expletive-laden meltdown during a show in Las Vegas in September, "is doing well," Dirnt said.

When the band announced on September 23 that its charismatic frontman would get help for substance abuse, it did not specify the nature of his problems.

The 2012 club tour was set to launch on November 26 in Seattle's Paramount Theatre and end in Tempe, Arizona, on December 10. The shows, which also included stops in California, Oregon and Nevada, will not be rescheduled.

The 21-city tour that was scheduled to start on January 7 in Green Bay, Wisconsin, and conclude on February 8 at the MGM Grand Garden Arena in Las Vegas will be rescheduled, the group's announcement said.

It was in Las Vegas at the MGM Grand that Armstrong's infamous onstage meltdown happened, during the iHeartRadio Music Festival.

Video from the event, captured on YouTube, shows Armstrong cursing profusely after cutting a song short. He then went on a profanity-filled rant, pointing to a sign indicating Green Day had only one minute left in its set, far shorter than he'd expected.

"You've got to be ... kidding me," said Armstrong, noting his longevity on the music scene and disparaging teen pop sensation Justin Bieber, who was not among the festival performers. "This is a ... joke."

Armstrong then slammed his guitar onto the stage, shredding it, and tossed its remnants into the crowd. He then flashed his middle finger and walked off the stage.

The band later issued an apology, telling fans "that our set was not cut short by Clear Channel and to apologize to those we offended at the iHeartRadio Festival in Las Vegas." iHeartRadio is a division of Clear Channel Broadcasting.

While fans can't see Green Day live onstage anytime soon, the group is moving up the release date of the album "Green Day Tre!" to December 11, 2012, from its original date of January 15, 2013.

"We feel bad we have to delay our tour, so to make up for it we want to give our fans the music earlier than we had planned," drummer Tre Cool said. "If we couldn't be there to play it for you live, the least we could do was give you the next best thing."

Armstrong was rushed to a hospital in Italy in September "due to illness," Dirnt said then in a video posted on the band's website.

After forming in 1987, the veteran punk band broke through in 1994 with the release of "Dookie," which sold 15 million copies and earned the band a Grammy for best alternative music performance.

Green Day continued to produce hit albums, like "Insomniac," "Nimrod" and "Warning." In 2004, the band took another major step forward with the release of "American Idiot," which won a Grammy for best rock album and inspired a "rock opera" years later by the same name.

The rockers have remained relevant in subsequent years, including capturing yet another Grammy in 2009 for the politically charged album "21st Century Breakdown."