I may have read Mr Lukather's tweets wrong but from what I gather the new album won't have ONE bassist per-se and will go through a roster of different ones for each tune. From what I can gather Leland Sklar has laid down a bass track for two of the songs there.
I knew Nathan East wouldn't be a permanent member (since he was always listed as a "special guest" on tour posters and stuff). This is a nice way for them to honour Mike Porcaro I think - it just proves how much they love the dude and don't think he can be replaced. One does wonder why Lukather didn't take over the bass parts himself but still - lovely gesture.
Will be very interesting to see who else shows up on the new album as "guest bassist". Wouldn't it be cool if they bought in Flea for one of the funkier tunes?
This album really is sounding more interesting by the minute.