On Friday, Upton was not in the lineup after a 15-game rehab stint with Triple-A Tucson that saw him hit .279 with three homers and 10 RBIs. He struck out 26 times in 61 at-bats.
Upton knows his role for the remainder of the season will be quite different. He's certainly not expecting to be playing every day.
"My role is a little bit different now, but I'm excited to be here and to be able to help out," Upton said. "The biggest goal is just to try to stay sharp.
"Obviously, you want to play every day, but if it means us winning, then it's something I can deal with."
Upton was required by Major League rules to come off the disabled list by Sunday at the latest. He has been out since July 9, when he strained the oblique during batting practice at Washington.
Dunn has started in right field in every game but one since he was acquired, and D-backs manager Bob Melvin is not inclined to remove his slugger from the lineup for Upton, but Melvin is still unsure about how Upton will be used.
"This year we have a few guys that are used to starting every day," Melvin said. "Somebody is not going to start on a particular day. It's just something they're going to have to deal with.
"We'll move it around based on what we feel is the best lineup on the particular day, do the matchups with lefty, righty or whatever. We can move some guys around and that's just the way it's going to be. We have 29 games left and we're going to try to run the best lineup out there each and every day we can."
To make room for Upton, the D-backs optioned outfielder Alex Romero to Triple-A Tucson. Romero likely will rejoin the club after Sept. 1, when rosters can expand to 40.
Mike Ritter is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.