The Dodgers had to clear room on their 40-man roster for top prospect Bobby Miller, who was called up from Triple-A to make his major league debut against the Atlanta Braves.
It was another major setback for May, who is only 25 but has battled injuries through his young career. He will be eligible to return to the Dodgers' active roster on July 17.
May was 4-1 with a 2.63 ERA in nine starts this season, but his velocity dropped off noticeably in his last start against Minnesota on May 17. He was lifted after only one inning with a strained right elbow.
The Dodgers knew he would miss at least a month, and now that timetable has been pushed back even more.
May missed much of the 2021 and '22 seasons after undergoing Tommy John surgery. He has made a total of just 20 starts over the last three seasons, going 7-5 with a 3.21 ERA in 101 innings.
May was first called up by the Dodgers late in the 2019 season and was their opening day starter for the pandemic-delayed 2020 campaign, making him the youngest Los Angeles pitcher to get that honor since Fernando Valenzuela in 1981.
During the 2020 postseason, May appeared in seven games — including three starts — as the Dodgers won their first World Series title since 1988.
Miller was the second straight rookie to start for the Dodgers, following Gavin Stone on Monday. Los Angeles has turned to its farm system to carry on while May and left-hander Julio Urías (hamstring) are on the injured list.