I'm relatively certain that Sony will be more than happy to lease Dr. Luke's services to other labels. Sony values Luke's skill and believe in his ability to foster up-and-coming talent. Understandably, they'd like to be closely associated with him, but I don't think they'd deny Luke the prospect of working with an artist from, for example, Capitol, provided Capitol is willing to cough up enough cash, or they can make some negotiation where they (Sony) would be entitled to a portion of the fees/royalties Dr. Luke would receive from the other label. I expect they'll demand a premium price for Luke's services, and consequently it might not be possible for some artists outside of Sony's roster to secure his services, but the girls with money, (girls like Katy Perry) should have no problem getting Dr. Luke to produce their songs, even if they're not part of the Sony team.
Katy needs the hits, Luke needs the cash - why would he agree to not work with the artist that brings him the most profit these days?
