Arrieta didn't hide his feelings after taking the loss in Monday's game against the New York Mets.
"I don't think our guys were ready to play," he told Matt Gelb of The Athletic.
However, he saved his most pointed criticism for Harper, who got the boot in the fourth inning after his second strikeout of the game.
"Look, I mean, he's got to understand we need him in right field," the former Cy Young winner said, according to Scott Lauber of Philly.com. "I don't care how bad the umpire is. He wasn't great for either side. I'm out there trying to make pitches, and he misses some calls. So what? We need him out there."
"It's troubling, yeah," he added. "I'm out there doing everything I can to win a game. I need my guys behind me, and they weren't."
Home plate umpire Mark Carlson ejected Harper shortly after he struck out looking in the fourth inning. The former National League MVP questioned Carlson's calls during his at-bats and then yelled something from the dugout, which prompted his ejection. He then ran onto the field and had to be restrained.
Carlson told a pool reporter that Harper's words from the dugout "warranted an automatic ejection" based on the "personal (comments and) language" he used, according to Tim Britton of The Athletic.
The umpire also said there was incidental physical contact during the argument which was caused by "Bryce bumping (manager Gabe Kapler) into me."
Harper conceded that he should have exercised more restraint.
"It just can't happen from my side," Harper said of his 12th career ejection, according to Lauber. "In a game like that against the Mets, (a) division rival, it just can't happen, for me, myself, and this team as well. We're a better team with me in the lineup and I've got to stay in there.
"I can't control what (Carlson's) zone is gonna be. I can control what I can do. I've just got to be better with that, tonight and going forward."