At right about this point in Deep Purple's career, Ritchie Blackmore was hospitalized with a case of mononucleosis. Their agent, sweating bullets at the million dollar tour he had booked for them, called another client of his in a panic. That client was Al Kooper (The Blues Project, Blood Sweat & Tears), himself just recovering from hospitalization with food poisoning. The agent dispatched Kooper to fill in for Blackmore. Kooper, more of a keyboardist than a guitarist, was dumbfounded that anyone would ask this of him, but gamely complied on the condition that it was just to humor the Deep Purple members until a better replacement was found. According to Kooper's book Backstage Passes and Backstabbing Bastards
, Kooper actually showed up to audition with Deep Purple who seemed more than happy to work around his deficiencies in a pinch, but in the end Kooper backed out and recommended guitarist Randy California (of Spirit) to fill in. Randy California agreed to the gig, but eventually on the first tour stop in Hawaii barricaded himself in his hotel room and refused to play, and alas, the tour was canceled.