Montgomery earned the save in Sunday's 4-3 win over Kansas City, allowing a hit while striking out one in a scoreless ninth inning.
Flores went 2-for-3 with a two-run homer and a double in Sunday's 4-3 win over the Royals.
Perez didn't factor into the decision Sunday against Houston, striking out two while allowing one run on six hits and two walks in 4.1 innings.
Dodd struck out the side to notch the save Sunday against Houston.
Riley is out of the lineup for Sunday's matchup with the Astros.
Bachar will serve as the Pirates' opening pitcher in a bullpen game Sunday against the Royals, Colin Beazley of the Pittsburgh Post-Gazette reports.
Lowe went 2-for-4 with a home run, two RBI and an additional run scored in Saturday's 6-5 win over the Royals.
Simon went 1-for-4 with a two-run home run in Saturday's 6-5 win over the Royals.
Olson went 3-for-5 with a two-run home run and an additional run scored in Friday's 6-2 win over the Astros.
Acuna went 1-for-5 with a two-run home run in Friday's 6-2 win over the Astros.
