The San Francisco Giants' rotation took another hit when right-hander Landen Roupp landed on the 15-day injured list with elbow inflammation.
The move announced Friday is retroactive to Wednesday for Roupp, whose MRI exam showed no structural issues, according to The Athletic.
The Giants are down to three regular starters with All-Stars Logan Webb and Robbie Ray and future Hall of Famer Justin Verlander.
"In flux," manager Bob Melvin said of his rotation. "Probably Tuesday we'll have to make a move. ... We have to be prepared for anything."
Roupp, 26, is 7-6 with a 3.11 ERA through 20 starts. He allowed four hits and struck out six in five scoreless innings in a 9-0 victory at Atlanta on Tuesday.
In a corresponding move Friday, San Francisco recalled right-hander Tristan Beck from Triple-A Sacramento. Beck, 29, is 1-0 with a 5.14 ERA in 11 games (no starts) this season for the Giants.