Fifty random fans will also receive a limited-edition bronze version of the Roberts bobblehead that night.
After playing an important role on the 2009 team, Roberts suffered through a miserable 2010 during which he spent much of the year at Triple-A Reno.
A longshot to make the roster at the start of Spring Training, Roberts led the Majors in batting average, and he not only made the team, but wound up with the bulk of the playing time at third base.
"It's awesome," Roberts said of winning the fan vote. "From where I was last year coming into this season, I never would have thought something like that would happen. So it's very special to know that I have fans that want me to win."
Roberts was the leader among write-in votes from fans on www.dbacks.com in the contest which ran from March 2 until April 30.