The person asked to remain anonymous because Upton's decision had not been made public. Upton's contract gave him the power to turn down the trade.
The Diamondbacks have a glut of outfielders and Upton, a former All-Star, is by far the most marketable. He is coming off a subpar season in which he was bothered for much of the time by a thumb injury.
Upton's rejection of the trade first was reported by FoxSports.com, which said Seattle offered four players in the deal.