Arrieta, who was placed on the 10-day injured list Wednesday, has been pitching through pain for several starts, but his inability to go more than five innings led him to shut it down. He was scheduled for an MRI on Thursday, and he will determine his course of action afterward.
"I wanted to try and make it work for as long as possible," Arrieta said. "I realized that I'm not able to give the team what it needs. The pain is something I can deal with, but it's the loss of feel and the ineffectiveness as the outings wear on. I think that the time is right to make it happen now and get a guy in the rotation that has pitched really well for us and give him an opportunity to get back to the form where he was at earlier in the season for us. I think we'll be in good hands."
Zach Eflin will rejoin the starting rotation and take Arrieta's spot on Saturday. First baseman Logan Morrison was recalled from Triple-A Lehigh Valley to take Arrieta's roster spot.
Arrieta won the 2015 NL Cy Young Award with theChicago Cubs. He has been mediocre since he joined the Phils on a three-year, $75 million contract in March 2018. The deal includes team options for $22.5 million in 2021 and 2022. Arrieta also can opt out after this season, but it's unlikely he'll give up the $20 million he is due next year.
He is 8-8 with a 4.64 ERA this season, after going 10-11 with a 3.96 ERA in 2018.
"Every fifth day, despite being uncomfortable and not being able to execute his pitches the way he wanted to execute his pitches, he gave us everything he had, and it was genuinely a heroic effort in a lot of ways," Phillies manager Gabe Kapler said.
Over his past 13 starts, Arrieta has a 5.76 ERA with 84 hits and 25 walks allowed in 65 innings.
"I would have liked it to go differently," Arrieta said. "I would have liked to pitch the remainder of the season healthy, but it's something that I really couldn't control. The spur stayed pretty dormant for seven to eight years, and it decided to give me trouble and get to a size now where this is the only option to me getting back to the pitcher that I am. And that's OK. This is what I have to do."
Arrieta, who has been pitching through pain this summer with sporadic effectiveness, told reporters that if he has the arthroscopic procedure, he'll "probably" not pitch again this season.
The Associated Press contributed to this report.
Realmuto rakes HR, RBI double in Phillies' win
J.T. Realmuto ropes his 16th home run of the season in the fifth inning, then gives the Phillies the lead late to preserve a victory over the Cubs.