Some of the most highly-anticipated albums of the summer have been delayed, including Mariah Carey's "Memoirs of An Imperfect Angel," Sean "Diddy" Combs' "Last Train To Paris" and Lil Wayne's "Rebirth."

Carey's "Memoirs," first slated for an August 25 release via Island Def Jam will now be available on September 15 according to the Universal Music Group business-to-business Web site. First single, "Obsessed," peaks at No. 11 on the Billboard Hot 100 this week.

Combs said via a video interview with MTV News release last week that this project's been delayed partially because it's "Jay-Z time and Drake time -- enjoy those guys. But the 'Train' is coming, baby," he warns. "Get your ticket, you don't want to be left out."

Lil Wayne's label publicist confirmed to that his release date has also been moved, although a new date hasn't been scheduled yet. "Rebirth" was last slated for a June 23 street date.

In related news, Amerie's long-awaited return, "In Love & War," which was originally slated for an August 11 release, will now be available on September 8. Lead single, "Why R U," reaches No. 62 on the Hot R&B/Hip-Hop Songs chart this week.