As of early Thursday afternoon, and even into early Friday morning, the Mavericks were certain they had an agreement with guard Yogi Ferrell on a two-year, $5.3 million contract.So in the immortal words of Ricky Ricardo, in the wake of Friday's news that Ferrell has pulled a DeAndre Jordan and reneged on yesterday's verbal commitment, we ask: "Wha' happened?" And to Ferrell: "Yogi, you got some 'splaining to do."So far the only thing resembling an explanation is Ferrell's agent Cervando Tejada telling Shams Charania of Yahoo Sports!: "We felt uncomfortable and will weigh our options."A Mavericks source told The News that the change of heart stunned the Mavericks' hierarchy, including coach Rick Carlisle, who had been in constant communication with Ferrell since last season ended.