D-backs sign Prado for four years The new contract settles Prado’s final year of arbitration and buys out the first three years of his free agency. FoxSports Jan 31, 2013 at 12:00a ET The Justin Upton trade suddenly looks better for the Arizona Diamondbacks. The D-Backs locked up infielder/outfielder Martin Prado on Thursday, signing him to a four-year contract. The deal, which was announced by the team, is for $40 million, according to a major-league source. Prado, 29, was the most significant piece that the Diamondbacks acquired for Upton in a seven-player deal last Thursday. The Atlanta Braves had offered Prado $6.65 million in arbitration before trading him. Prado had requested $7.05 million. The new contract settles Prado’s final year of arbitration and buys out the first three years of his free agency. Prado, who will play third base for the D-backs, batted .301 last season with a career-high 42 doubles, 10 homers, 70 RBI and a .796 OPS. He led the National League with 60-multi-hit games, and is a career .301 hitter with a .780 OPS.