Dominguez was held out of Saturday's doubleheader against the New York Mets after experiencing tightness in his right triceps in the morning and last pitched on Wednesday. The move was made retroactive to Thursday.
"I take it seriously," Dominguez said Saturday. "I have to take care of my arm. It's the only way I can compete.''
Dominguez, who has been an anchor at the back end of Philadelphia's bullpen, returned this season after a recovery period of more than two years following elbow issues and Tommy John surgery. He replaced Corey Knebel as the Phillies' closer midway through this season and is 6-4 with nine saves and a 1.64 ERA in 44 innings.
Knebel, meanwhile, was transferred to the 60-day IL and will miss the remainder of the season. Manager Rob Thomson told reporters that Knebel, who signed with the Phillies in free agency before this season, has a tear in the capsule of his right shoulder. Knebel finishes the 2022 season 3-5 with 12 saves and a 3.43 ERA over 44⅔ innings pitched.
The Phillies acquired David Robertson before the trade deadline, giving them a closer now to cover them during Dominguez's absence.
Robertson, who had three saves and hadn't allowed a run in eight innings since joining the Phillies entering Sunday, blew the save against the Mets on Sunday when he allowed a two-run home run by Mark Canha in the ninth inning. Robertson took the loss as the Phillies fell 10-9. He was pitching for a second straight day after pitching two scoreless innings and throwing 36 pitches to get the save in a 4-1 victory in Game 2 of the doubleheader on Saturday night.
Philadelphia recalled right-hander Tyler Cyr from Triple-A Lehigh Valley on Sunday in a corresponding move.
The Associated Press contributed to this report.