Manager Bryan Price said the left-hander was sore and would be further examined Monday after the club returns home.
Peralta has been a pleasant surprise for the Reds, graduating from his main role as a lefty specialist. He has a team-high 63 appearances, and carried a 3.05 ERA before yielding four runs in the eighth on Saturday.
"He was really in no different position than any of the young starters; somewhat untested even though he did pitch last year," Price said. "And then he pitched so well in that environment he's been a primary late-inning pitcher for us."
Come one, come all
Peralta is the latest injury loss among many. Price noted his surprise that right-hander Tim Adleman leads the staff with just 119 1/3 innings. Only one other pitcher, injured righty Scott Feldman (111 1/3), has eclipsed the 100-innings mark. The Reds have used 28 pitchers -- 15 of them starters -- this season, a number that doesn't include second baseman Scooter Gennett.
Price is a former pitching coach with the Mariners and D-backs. In 2003, his Seattle club used five starters the entire season.
"I tell you, this is a season to remember in that regard," he said.
Asked if it was really a season to forget, Price responded, "No, no, it's unforgettable, I know that."
Reds catcher Tucker Barnhart came off three-day paternity leave Sunday and will rejoin the club in Cincinnati on Monday.
Bob Cohn is a contributor to MLB.com based in Pittsburgh. This story was not subject to the approval of Major League Baseball or its clubs.