Houston Press
http://blogs.houstonpress.com/rocks/...almost_hap.php
By Corey DietermanWed., Sep. 26 2012
Yes and Zeppelin? 5 True All-Star Near-Collaborations
#4 Ok, you probably didn't think of this one, but if you were a blues-rock fan in the '70s, it might not have sounded like a bad proposition. Dave Walker was a long-term member of Fleetwood Mac in their serious blues-rock days before they got Stevie Nicks and went pop. When Ozzy quit Sabbath in 1978, Sabbath hired Walker, who had been recording solo since getting bucked (get it?) from Fleetwood Mac.
They only managed to make a few recordings for what would eventually become Never Say Die. You can listen above to an early version of "Junior's Eyes" featuring Walker on vox. Unfortunately for Walker, Ozzy wanted back in when he saw the band was going on without him, so Dave was out and Oz was back in (at least until he left again the next year).