The D-backs and Yankees have agreed on the structure of a deal that would send Randy Johnson back to Arizona, a source with knowledge of the negotiations said. The D-backs are likely to be granted a 72-hour window at some point Thursday to begin negotiations with Johnson on an extension that would keep the 43-year-old in Arizona through the 2008 season. The teams have informed the Commissioner's Office of the specifics of the trade, The Associated Press reported, citing a baseball official as its source.