Tickets for the postponed shows will be honored at the make-up dates, and refunds will also be available at the point of purchase, the press release said.

Backstreet Boys members Nick Carter, Kevin Richardson, Howie Dorough and Brian Littrell made the announcement about McLean on Monday’s (7/9) edition of MTV's "Total Request Live." The group attributed some of McLean’s troubles to the recent death of his grandmother.

"She just passed away recently and that kind of just sent it over the edge," Richardson said during the appearance.

Dorough added that, though the group is currently planning to resume touring immediately following McLean’s 30-day treatment, the group is prepared for an additional delay.

"A.J.'s health is most important to us," said Dorough. "We love him as a brother. If, after 30 days, he needs more time than that, we’ll give him time. We're just really keeping our fingers crossed and counting on A.J. coming back. He knows he has a problem. He wants to get it fixed."

In a joint statement issued following their MTV appearance, Carter, Richardson, Dorough and Littrell said that they had been advised by some to keep McLean’s condition a secret, but had chosen to reveal the truth nonetheless.

"It's been suggested that we not be so forthcoming about this situation, as many artists in the industry have in the past," reads the statement, "but we feel compelled as a group to be honest with our fans and not let them down. AJ is our friend and our brother and we whole-heartedly support him during this difficult time. Fortunately, AJ has realized he can't solve his problems by himself."

Earlier in the day on Monday (7/9)--and prior to the group’s announcement about McLean--tour promoter Clear Channel Entertainment (formerly SFX) announced that the group’s Monday, Tuesday and Wednesday night performances in Boston had been postponed due to Carter's fractured right hand.

Backstreet Boys last performed at Boston’s FleetCenter on Saturday night (7/7), and were scheduled to give three more performances at the venue on Monday, Tuesday and Wednesday nights (7/9-7/11). Carter was wearing a cast on his injured right hand during Saturday night’s performance and during the group's appearance on MTV on Monday.

Backstreet Boys’ tour kicked off last month, and was originally scheduled to run until Aug. 31.

LiveDaily Contributing Writer Christina Fuoco contributed to this report.