Sources: Justin Upton, D-backs agree

The Arizona Diamondbacks have reached an agreement with right fielder Justin Upton on a six-year contract worth $51.25 million, sources told ESPN.

FoxSports.com first reported that Upton and the Diamondbacks were closing in on a deal, expected to be announced Wednesday.

The contract would cover all three years in which Upton, 22, would be eligible for salary arbitration, as well as his first two years of eligibility for free agency. Without a new deal, Upton would have been eligible for arbitration after this season.

In 2009, Upton hit .300 with 26 home runs and 86 RBIs -- all improvements over his 2008 production.