Marissa Mayer has told Yahoo (YHOO) execs chief revenue officer Michael Barrett is leaving, Kara Swisher reports - Barrett was reported to be "negotiating his exit" yesterday. Meanwhile, new COO Henrique de Castro might not be able to start until year's end, leaving Yahoo without a sales chief in the interim. That could cause further issues for Yahoo's sales force, reportedly feeling overlooked in the Mayer era. Sources tell Swisher Mayer "has spent a negligible amount of time with sales execs." Update: Swisher now reports de Castro will start on Nov. 12.