The latest came Tuesday night when the right-hander gave up eight runs in 4 2/3 innings as the D-backs fell to the Rockies, 10-5.
It was the D-backs' 10th attempt to reach the .500 mark since April 24, and they are 0-10 now in those games.
Anderson (3-2) came into the game having allowed a total of three runs over his last three starts, and he held the Rockies to one run over the first three innings before the wheels came off in what would become his shortest start of the season.
Nolan Arrenado hit a solo homer in the fourth and then helped key a six-run fifth with a three-run blast.
"He just elevated the ball too much, and they had good at-bats against him," D-backs manager Chip Hale said.
In fact, the Rockies' at-bats were so good, Hale was concerned that they might have known what was coming.
"I don't remember one swing at a ball out of the zone," Hale said. "So we'll have to check and see if he was tipping in any way, because they seemed like they knew what was coming. His ball was up in zone, his fastball was running back over the plate. So we'll look at the video and just see if there's anything he's doing that's hurting his chances."
Anderson had a pretty good idea what cost him, and it wasn't that he was giving away his pitches. It was simply the location of the ones he threw.
"You can't leave the ball up in this park," Anderson said. "They're going to make you pay for it. It's just something to learn from. I've just go to keep the ball down. That's the only thing I can really take from this. Baseball you have those days, and you learn from them."
Anderson speculated that the reason he couldn't get the Rockies to chase any pitches out of the zone was because he was not in the zone enough to begin with.
Breaking balls tend to break less at high altitude and sometimes pitching at Coors Field can get into a pitcher's head. Anderson swore that wasn't the case with him.
"I think it could have just been anywhere," Anderson said of the way he pitched. "Just a bad outing. Here, if you give up fly balls, they're going to go farther than most places just due to the altitude. I just think you should rack it up as a bad outing, one of those during the season. Hopefully, I don't have any more."