Earlier this year, Khan signed a multi-fight promotional deal with Eddie Hearn, who also promotes Brook.
Khan would enter the ring as a tremendous underdog against Crawford, after getting dropped and rocked on at least two occasions in his most recent bout against Samuel Vargas - who was carefully selected for Khan's second bout under Hearn.
Khan spoke to the Daily Mail about the potential title fight, saying that he isn't anxious about not getting to fight Brook next if that is the case.
"We made a proposal to Amir Khan and we will wait to hear back", Arum said.
"It's Crawford. Crawford has the pound-for-pound title and I've got that fight right in front of me, so I want to take that one". The Brook fight is always going to be there.
Crawford (34-0, 25 KOs), 31, of Omaha, Nebraska, who has won world titles at lightweight and then became the undisputed junior welterweight world champion past year, moved up to welterweight in June and knocked out Jeff Horn in the ninth round of a one-sided fight to take his title.
"I feel like he's always going to be there so I'd rather fight these world champions, fight for these pound-for-pound titles because I know Kell is always going to be there", he told Sky Sports News.
Crawford (34-0) is widely considered as the current pound-for-pound king in boxing, and the American's team have tabled Khan an offer for a world title fight in the United States.
"But there are other fights out there at the moment, like pound-for-pound champions, that is on the table for me". And not only that, when will it be in the welterweight division which it is at the moment, ' he added. 'Say I take the Brook fight, it might not be there then and I might not get the opportunity again.
"And I think that's a fight which might never, ever come in my lifetime again". After almost two years out, he returned to the ring in April this year with a first-round stoppage of Phil Lo Greco before climbing off the floor to beat Samuel Vargas in September. Brook, the Bolton fighter claims, has yet to agree to those stipulations. It was reported later on Monday that Khan has been offered a $5million guarantee to fight Crawford on March 23 at Madison Square Garden in NY.
While Collazo has signed on for the challenge to face the Nebraska native, Crawford has yet to sign any contract.