Surely Astana or Trek sign Quintana.
Trek doesn't want anyone connected to shady business, afaik. I know there are some exceptions in the past (Mattias Skjelmose, Contador post-ban, etc.) but afaik it has been reported that when the situation involving Toon Aerts gets solved, he isn't staying in his past team because Trek doesn't want the exposure of the positive case situation in a rider of their team and is now a brand policy.