Former Guns N' Roses star MCKagan performed with the singer in Velvet Revolver before Weiland was sacked and made a return to his ex-band Stone Temple Pilots.
Weiland was kicked out of that group earlier this year (13) and replaced by Linkin Park's Chester Bennington, and MCKagan admits he was sorry to hear of his former colleague's new problems.
He tells Billboard.com, "You could kind of see it coming, I suppose. It's a sad situation any way you look at it. That guy... You hope (Weiland) pulls it together; I shared enough good times with that guy that I wish him nothing but the best."
Weiland is currently locked in a legal battle with his former Stone Temple Pilots bandmates - they sued him for allegedly sabotaging their recent 20th anniversary tour with his bad behaviour, while he has filed a countersuit in a bid to stop them using the group's name without him in the line-up.