Adler founder and former Guns N' Roses drummer Steven Adler has entered rehab, forcing his band to postpone their summer 2013 U.S. tour. Over 40 dates were scheduled through early September, which representatives of Adler say they hope to reschedule this fall.

The nature of what set Adler back to rehab has not been completely revealed, but a statement said that Adler checked into the facility to "continue working on his sobriety." Still, sources indicate it may not be as serious as some of his previous dependency issues. According to 107.9 the River in Casper, Wy., who broke the story, this is a minor incident compared to his previous relapses.

“We are truly sorry to all of the fans and promoters who were looking forward to seeing us on the road, but right now Steven’s health is the most important thing” Adler singer Jacob Bunton added in the statement. “We hope to make it up to everyone when Steven recovers.”

The location of the rehabilitation center was not disclosed, nor was the length of his stay. Adler's struggles with substance abuse are well-known, including a heroin addiction that prompted his exit from GNR, and a 1996 stroke fueled by a mix of cocaine and heroin.

Adler, the band, is scheduled to begin a European tour on Sept. 20. The month-long run of dates will take them through Spain, the U.K., France, Holland, Germany, Italy and Switzerland. Those dates have yet to be altered or postponed.