ESPN (Marc Stein) reports: With the New Jersey Nets poised to complete a blockbuster deal to send Jason Kidd back to Dallas on Wednesday night, Mavericks reserve forward Devean George has unexpectedly exercised his right to block the trade, according to NBA front-office sources. Sources close to the situation told ESPN.com that the teams verbally agreed to the deal earlier Wednesday and were preparing to submit the trade for league approval when George informed the Mavericks that he wouldn’t consent to being included in the deal, which is his right based on a rare provision in his one-year contract.