"Our bullpen has been taxed over the past 10 days and I felt as though we needed a fresh arm," said Padres manager Bud Black. "Robbie's last couple performances have been such where I think there was a couple things that required immediate attention, and he'll get that in the Minor Leagues."
Erlin allowed 12 runs on 11 hits and walked seven in his first two career starts on the road (at Boston and Washington). That's a 14.08 ERA over 7 2/3 innings.
"Trying to be too fine and felt like I tried to do a little bit too much," Erlin said. "That comes from a lack of execution."
In his first two starts, both at Petco Park, Erlin produced solid outings. On June 1 against the Blue Jays he allowed eight hits and gave up two runs in 6 2/3 innings. His next start came on June 26 against the Phillies, where he scattered four hits and two runs in 6 1/3 innings.
"I think the biggest difference is the fastball command," Erlin said about his first two starts and last two. "The offspeeds were a little bit inconsistent at times in all four of them. I was able to get that feel back in the first two, and finish the game strong. Fastball command is what I relied on in the first two and I didn't have it in the second two. It's tough to get by."
The Padres have not announced who will start Friday against the Giants in Erlin's spot.
Jamal Collier is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.