He said after the game he has been dealing with an elbow problem.
"I can't explain it right now," Gonsolin said. "I don't know what it is exactly, so I try not to."
Roberts said Gonsolin had been pitching through an "arm issue" for at least a month. Gonsolin missed 40 games late last season with forearm tightness.
On Friday, Gonsolin tied Don Sutton's 1973 record for homers allowed in a start during the Dodgers' Los Angeles era. Gonsolin had never given up more than two homers in a start, but he flopped when the Dodgers needed him to eat innings in the first of three games between these clubs in just over 24 hours. They are playing a split doubleheader Saturday to avoid the looming impact of Hurricane Hilary, which is expected to hit Southern California as a tropical storm this weekend.
Gonsolin's struggles forced the Dodgers to get deep into their bullpen Friday -- even to infielder Miguel Rojas, who pitched a perfect ninth.
The Dodgers brought in a reliever in a corresponding move, recalling left-hander Bryan Hudson from Triple-A Oklahoma City. Hudson has a 7.94 ERA in three appearances for the Dodgers this season.
An All-Star in 2022, Gonsolin fell to 8-5 with a 4.98 ERA through 20 starts this season. He has struck out 82 batters, walked 40 and allowed 19 home runs in 103 innings.
The 29-year-old owns a 34-11 career record with a 3.19 ERA in 79 games (71 starts) since making his debut with the Dodgers in 2019.
Reuters and The Associated Press contributed to this report.