Ransom homered and drove in the go-ahead run in Friday night's 5-4 win and has hit .345 with three homers and 10 RBIs in 29 at-bats since being called up from Triple-A Reno.
Meanwhile, Roberts has struggled, with a .164 average, one homer and 10 RBIs in 73 at-bats.
"Cody and Ryno, just trying to keep Ryno involved," Gibson said. "Keep them both involved, actually."
Gibson was asked if it was difficult to take Ransom out, given the game he had the night before.
"He's on the bench if we need him," Gibson said. "I just don't look at it that way. I think when you make up a lineup, in general, you can kind of be very similar on most days. I think people might perceive these are the best eight guys. The reality of it is I think it's just the opposite. I think the more you mix it up, the stronger your team becomes in the end."
With that in mind, Henry Blanco was behind the plate in place of Miguel Montero.
"I'm just rotating guys," Gibson said. "I mean, I can't play Miggy every day -- it's a long season and we're early in the season."
Gerardo Parra was also out of the lineup, with rookie A.J. Pollock was in his place in center. Pollock has just 25 at-bats since being called up April 18 when outfielder Chris Young got hurt.
"A.J. has to play," Gibson said. "He's a young kid. Ideally, he'd be playing every day for his development."