Rosie O'Donnell RIPS Lindsay Lohan -- She's a DISGRACE to Liz Taylor

Rosie O'Donnell is on the warpath over the casting of Lindsay Lohan in the new Liz Taylor biopic ... saying LiLo simply isn't "capable" to perform the role because her personal life is still a disaster.

Rosie was on the "Today" show with Matt Lauer and Donny Deutsch ... when it was announced that Lohan will play Taylor in the upcoming Lifetime movie, "Liz and Dick."

O'Donnell instantly made her feelings known -- "I feel very sorry for her ... I think she needs a lot of time away ... She's had a lot of trouble doing every single movie, including SNL. She was out and not in rehearsal. I think she's not in a place to work."

When Deutsch suggested, "She's our generation's Elizabeth Taylor" ... O'Donnell lost it.

Rosie continued, "I don't think she's right for the role and I don't think she's capable at this point to portray that character."