Acquired from the Athletics in the offseason for Jarrod Parker, Cahill began his D-backs career on the right foot, allowing just two earned runs over his first 13 1/3 innings with the club.
But since then, the 24-year-old has surrendered four earned runs on three occasions and three earned runs once.
The only bright spot in the middle of the consecutive poor starts was a 7 1/3-inning performance against the Nationals, when he gave up one run and got the win.
Cahill will try to find consistency when the D-backs take on the Rockies in the finale of a two-game set Thursday at Coors Field.
In his last start, Cahill was mowing down the Giants lineup but hit consecutive batters with two outs in the fifth then allowed a two-RBI double to Matt Cain to derail his day.
Cahill took the loss, ending the D-backs' streak of nine consecutive wins against the Giants.
"It's frustrating and I'm trying to forget about it," Cahill said after the game. "You can't take anything for granted. I had two strikes on the guy and I end up hitting him. I'm thinking, 'The pitcher is coming up,' and he ends up getting a hit."
On the mound for the Rockies on Thursday will be Juan Nicasio. The righty is coming off arguably his best start of the year, even though he received a no-decision in it.
Nicasio tossed seven innings against the Dodgers on Saturday, allowing just one earned run on five hits before Los Angeles won the game, 2-1.
Nicasio gave up six runs and eight hits in five innings in his previous start, a 7-2 loss to the Braves on May 6 at Coors Field.
"When I have command of my fastball, I'm happy, I'm good," Nicasio said after the Dodgers game. "I was not worried about my last start. Everybody has a bad day, and that day in Denver I didn't have command of my fastball."
D-backs: Young heads to Triple-A
Chris Young is heading to Triple-A Reno and hopes to play Thursday. He is not sure exactly when he will return to the D-backs lineup, but he knows it's not far away.
"It's getting to the point where you can smell it. I don't have an exact date yet, though," Young said. "Believe me I want to be out there so bad."
Young injured his shoulder crashing into the wall April 17.
In three games with Class A Visalia, Young went 4-for-13 with three doubles, a grand slam and seven RBIs.
"It's not the results that I've been focused on," Young said. "The main thing is to be swinging pain-free and not to have any pain when I swing and miss."
Rockies: Young returns from bereavement
Rockies utility player Eric Young Jr. and his father, former Rockies All-Star and current D-backs first-base coach Eric Young, were together again Wednesday night, after spending a sad occasion together over the weekend.
Otis Young, father of the coach and grandfather of the player, died last week.
"He had been sick the last several years, been in and out of the hospital, so he's in a better place," Young said. "He knew we were there. We got there before he passed.
"Throughout this whole journey playing ball, he was a man of few words. He pretty much kept it simple. He'd always tell me, 'Go hit that ball, boy.' That's what stuck in my head."
The Rockies activated Young on Wednesday, and placed third baseman Chris Nelson in the 15-day disabled list with soreness in his left wrist that has been lingering since incurring the injury at Pittsburgh on April 25.
"I was itching to get out here," Young said. "I was missing my teammates. I was obviously watching the road trip. I'm just thankful to be out here playing this game. It really put everything into perspective."
The D-backs' Daniel Hudson threw in a game at extended spring training Wendesday. He tossed 2 1/3 innings, giving up two hits and two earned runs.
Rockies veteran Jamie Moyer earned his second win of the season Wednesday, outlasting D-backs rookie Patrick Corbin, who is more than 20 years younger than him.