According to both sources, the Diamondbacks asked for two-time All-Star Starlin Castro in return for Upton. The Cubs, trying to build a solid base of young players in their somewhat depleted system, balked at trading a 22-year-old shortstop for a 25-year-old right fielder and cut off talks.
Upton, who has been offered around baseball in trade conversations since the winter meetings in December, vetoed a trade to the Seattle Mariners 10 days ago. While the Diamondbacks appear to want to deal him, general manager Kevin Towers said last week that they expect quality in return.
"We are not interested in giving away any of our young talented players," Towers said last Saturday at the Professional Scouts Foundation dinner in Los Angeles. "My job is to get the best players in order to win championships here in Arizona. That said, someone will have to give us equal value if we move one of our top players."
Neither Towers nor the Cubs would comment when contacted by ESPNChicago.com. In his contract, Upton has the Cubs, the Boston Red Sox, the Toronto Blue Jays and the Mariners on his list of four teams to which he could veto a deal.
Upton, a young five-tool player, has three years remaining on a contract worth $38 million. He is a career .278 hitter with 108 home runs since breaking into the big leagues in 2007 at age 19.