As Mark told it in "Cubs Nation" by Wojo (fantastic book, read it read it read it), the Cubs kept telling him that they'd get a deal done with him after they took care of their other offseason needs and then ultimately just didn't make him an offer, leaving him to fend for himself with very little time left in the offseason. He claimed that he would've understood if they'd kicked him out the door in favor of Choi as long as they'd been honest about it.