In the Porcaro biography, it mentions that after he toured with Steely Dan in 1974 and when they were back in LA, Walter Becker called Jeff and said he was writing for their next album, and asked if he could borrow a drum set. Jeff assumed that he would be playing some of the tracks, as he played all but one track on Katy Lied. Since Steely Dan was his favorite gig, he was pretty disappointed that he didn’t get a call for The Royal Scam.
Katz was doing a final mix in NYC of Aja 6 months after it was recorded.I just started watching this - it's the first six minutes. Great story - I'm also reading the Steely Dan bio - and back then it was all about the drummer.