As expected, left-hander Hyun-Jin Ryu was activated from the disabled list to start Thursday's game. It was Ryu's first outing in 21 months after a shoulder injury that required surgery.
Ryu lasted just 4 innings, allowing six earned runs on eight hits and two walks while striking out four.
"Overall, I felt really great," Ryu said through a translator. "My shoulder felt really great. I didn't see any issues."
The Dodgers fell 6-0 to the Padres.
"The biggest part was getting him out there, and it was a victory in itself," Dodgers manager Dave Roberts said. "Up until the fifth inning where he ran out of gas and velocity started to slip, I thought he threw the ball well."
The Dodgers also got some help for a tired bullpen, calling up right-hander Carlos Frias from Triple-A Oklahoma City. Frias came on in relief Thursday and pitched four scoreless innings, allowing two hits and a walk with three strikeouts.
To make room on the 25-man roster, outfielder Will Venable was designated for assignment for the second time this season. The Dodgers also optioned left-hander Luis Avilan back to Triple-A Oklahoma City.
Ryu had not pitched in the majors since Sept. 21, 2014. He ended that season with a 14-7 record and a 3.38 ERA, with 139 strikeouts in 152 innings. He did not have shoulder surgery until May of last year.
He posted a 4.23 ERA over eight minor league rehab starts in advance of his return. Ryu had a setback this spring with a leg injury and another during his rehab stint, when he worked through shoulder soreness.
Frias is making his second appearance with the Dodgers but did not pitch the first time he was called up. In 10 minor league games this season, Frias was 3-3 with a 3.95 ERA. Five of his 10 outings were starts.
"We have so much quality depth in our rotation," Dodgers catcher A.J. Ellis said. "We'll see Hyun-Jin of 2013-14 really soon. He's going to be a huge weapon for us in the second half."
Information from The Associated Press was used in this report.