Zack Greinke and the Arizona Diamondbacks finalized their $206.5 million, six-year contract on Tuesday, a deal with a $34.4 million average salary that is the highest in baseball history. The Diamondbacks beat out NL West rivals Los Angeles and San Francisco to sign the major league ERA leader and runner-up for the NL Cy Young Award, who helped the Dodgers win their third straight division title this season. ''Zack fills the frontline starter need we've been exploring for a while,'' Diamondbacks general manager Dave Stewart said in a statement.