"It was one of those games where I was battling myself out there," Cahill said after losing 3-1 to the San Diego Padres on Monday.
Cahill (3-10) allowed three runs and five hits while walking six and striking out five. He departed after allowing Yasmani Grandal's single and Jedd Gyorko's double in the fifth.
"It's been frustrating because I was making strides toward pounding the zone and limiting the walks," he said. "Then a day like this, it just all kind of crumbled down and you know you're back to square one. It's no fun when you're kind of fighting against yourself rather than the other team."
Manager Kirk Gibson didn't think there was a common theme to Cahill's last two starts.
"I don't think it was that bad," Gibson said. "When he got ahead, he got in trouble after that because he couldn't put them away. He pitched deep in the counts. I wish I had the answer to help him figure it out. He has too good of stuff to go four innings and throw 100 pitchers."
But Gibson does know that six walks are "way too many in four innings. He wiggled out of it the best he could."
Spangenberg, the Padres' first-round pick in the 2011 draft, had his contract selected from Double-A San Antonio and started at third base. He came up with the bases loaded and one out in the fifth inning and singled to right off Eury De La Rosa for a 3-0 lead.
Spangenberg is the third player in Padres history to have multiple RBIs in his big league debut.
Ross deflected a fifth-inning comebacker by Didi Gregorius with his glove but stayed in the game. In the sixth, after Ross allowed a leadoff single by David Peralta, manager Bud Black and a trainer came out to check on the tall right-hander. Black left Ross in the game. He allowed two more singles, including an RBI hit by Miguel Montero, before striking out the side.
Ross (13-12) allowed six hits, struck out eight and walked two. It was his 14th straight start of going six or more innings and allowing six or fewer hits. He is 7-6 with a 1.93 ERA in that stretch.
Kevin Quackenbush struck out the side in the ninth for his second save in three chances.
LOTS OF KS
The Diamondbacks' 6-7-8 hitters struck out 10 times in 12 at-bats. Jake Lamb and Nolan Reimold each struck out four times while Gregorius struck out twice.
The Diamondbacks stuck out 13 times total.
Arizona: The Diamondbacks reinstated OF Cody Ross (strained left calf) from the 15-day disabled list and RHP Daniel Hudson (reconstructive elbow surgery) from the 60-day DL. Hudson likely will work in relief. He hasn't pitched for Arizona since June 26, 2012, when he tore the ulnar collateral ligament in his right elbow against the Braves.
San Diego: The Padres transferred 1B Yonder Alonso (right wrist surgery) and LF Carlos Quentin (bone bruise, left knee) to the 60-day DL to make room on the 40-man roster for September promotions RHP Leonel Campos and Spangenberg.
Arizona: Wade Miley (7-10, 4.30 ERA) has no record and a 3.86 ERA in two starts vs. San Diego this year. He is 1-6 with a 4.96 ERA in 11 career starts against the Padres.
San Diego: Odrisamer Despaigne (3-5, 2.54 ERA) is 1-1 against Diamondbacks this year, including a 5-1 loss at Arizona on Aug. 22.