The former light-welterweight world champion has been out of action since May after deciding to have surgery on a long-standing hand injury in the wake of his sixth-round knockout defeat to Saul Alvarez.
However, with Khan looking to return to the ring in April, he has acknowledged that a showdown with rival Brook is likely to represent his "next big fight".
The 30-year-old told Bolton News: "I can't wait to get in the ring at 147 again, which is my weight division. I think these next few years are going to be my best.
"I have been on a downer since the last fight with the injury and all that. Now I cannot wait to get back in training with my trainer Virgil [Hunter].
"I am going back down to 147 and still have that position as number one mandatory [for the WBC title] but I think that [Kell Brook] will be the next big fight for me. It would be massive - a super fight."