Mahle took a no-decision Thursday against the Reds, striking out two while allowing five runs on six hits and two walks in five innings.
Atlanta recalled Waldrep (elbow) from Triple-A Gwinnett on Thursday and placed him on the 60-day injured list.
Atlanta selected Hernandez's contract from Triple-A Gwinnett on Thursday.
Ralston (0-2) earned the loss after allowing two runs and on three hits and no walks over 1.1 innings against the Cubs on Thursday. He struck out two.
Atlanta placed Perez on the 15-day injured list Thursday with lower-back inflammation, Jesus Cano of The Athletic reports.
Phillips did not factor into the decision in Thursday's 2-1 loss to the Cubs, allowing no runs on three hits and four walks over four innings. He struck out two.
Acuna (leg) will start in right field and will bat second in Thursday's game against the Reds.
Marlins manager Clayton McCullough said Thursday that Alcantara will not make a start this weekend against Atlanta, Stephen Strom of Marlins Radio Network reports.
Stowers is absent from the lineup for Thursday's contest versus the Cubs.
Stowers went 1-for-4 with a two-run home run in Wednesday's 3-2 win over the Cubs.
