In his first four starts of the year, Cahill went 0-4 with a 9.17 ERA, and the team decided to shift him to the bullpen and call up right-hander Mike Bolsinger to take his place in the rotation.
In two relief appearances since, Cahill has not allowed a run in four innings.
"Just throwing the ball with much more confidence right now," Gibson said.
Bolsinger allowed seven runs (six earned) over four innings in his first Major League start Saturday night at Dodger Stadium after having thrown out of the bullpen once last week.
"It's how you respond to it," Bolsinger said after the start. "Each time I've been out there, I've kind of learned. I learned a lot from my first time out and I kind of learned a lot from this start. Hopefully I can take it on to the next one."
Gibson said Sunday that as far as he knew, Bolsinger would start Thursday against the Cubs at Wrigley Field.
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.