That battle was once again on display Tuesday afternoon at AT&T Park as Cahill did not make it out of the fourth inning in a 7-3 loss to the Giants, who celebrated their home opener.
"He just struggled with being able to locate his pitches," D-backs manager Kirk Gibson said. "You have to talk to him and ask him how he feels about it."
The sellout crowd was treated to festive pregame ceremonies, and they did not have to wait long before their beloved Giants gave them something to cheer about.
Angel Pagan drew a walk to lead off the bottom of the first and Brandon Belt continued his bludgeoning of the D-backs when he hit a 2-1 fastball that badly missed its intended location into the right-field bleachers for a 2-0 San Francisco lead.
"He missed his spots," Gibson said. "Leadoff walk and then he missed his spot on Belt. It was supposed to be down and away and it was down and in, and he's hit enough home runs to where we know that's not really where we want to go."
Cahill gave the D-backs some semblance of hope when he kept the Giants off the board in the second, while the D-backs pushed across an unearned run to cut the lead in half, but things unraveled quickly for Cahill in the third when the Giants scored three runs to go up 5-1.
Gibson had seen enough of Cahill after he allowed a two-out single in the fourth, and he was blunt when asked if the team could continue to get such a subpar performance from a member of the starting rotation.
"No," Gibson said. "We're going to have some discussion. You've got to have better than that. It wears on everybody."
For his part, Cahill is at a loss to pinpoint a reason for his struggles.
"My bullpens have been better," Cahill said. "I'm just trying to take it into the game. You get in those situations where there are guys on, you try to do too much and you try to throw too perfect of a pitch instead of letting your stuff work. I felt like today if I fell behind, I'd leave something middle, and if I got ahead, I'd try to make too perfect of a pitch to try to strike somebody out. I just have to realize what kind of pitcher I am."
But why is he unable to carry over a good bullpen into the game?
"I don't know," he said. "If you knew that, then you could be a pitching coach, I guess. If you go out there and the hitter stands in, you just try and do too much. It's something to work on."
Catcher Miguel Montero has given the situation plenty of thought and he, too, does not have an answer.
"It's just different," Montero said. "He throws really good in the bullpens. His bullpens are phenomenal. I keep telling myself he looks good. 'We've got a good chance right here, he looks good.' And then we cross the lines and he's just a different cat."
Speaking of things that the D-backs are unable to solve, you can add Giants starter Tim Hudson to the list.
The right-hander tossed 7 2/3 scoreless innings in Arizona last week and Tuesday he allowed three runs (two earned) and struck out four in eight innings.
After falling behind in the count often against him the first time around, the D-backs tried to be aggressive early in the count this time, but it did not provide them with a different result as the veteran used the approach against them.
"I guess guys are fighting to get to the bat rack to swing off me," Hudson said. "They're not being too patient. But I enjoy when hitters go up there and they want to hit. Right now I'm pounding the strike zone with a lot of my pitches, and it's forcing other teams to swing the bat. If I can do that, stay out of the middle of the plate, I can go deep into the game and keep those guys behind me looking good, making good plays behind me."
That's what the D-backs keep hoping for from Cahill.