Hellickson said he hasn't been fighting any kind of shoulder problem.
"No, I just felt a little weak, I guess, the last few starts," Hellickson said. "I got an X-ray and everything was fine. There's really no soreness. No pain or anything, a little fatigue. Take a few starts off."
Hellickson made no bones about it, he wanted to make his scheduled start Wednesday night, but was overruled.
"He wasn't highly pleased about it," manager Joe Maddon said. "But we sat down and I talked to him about it. And just tried to reason with him the whole logic behind it, because he really believes he can still pitch [Wednesday]. But we just like the idea of backing off right now. We don't consider it to be critical. We just want to make sure he's able to pitch in the World Series this year."
The plan is for Hellickson to miss his next two starts and Archer to fill his spot.
"Arch is ready to roll, really calm about the whole moment," Maddon said. "We had a nice conversation. All I want to do is have him go out there [Wednesday] and be himself. Don't worry about the scouting reports. Go out there and throw his fastball see what happens."
Archer was 4-8 with a 4.81 ERA in 14 starts for the Bulls. He is looking forward to fulfilling a dream Wednesday night.
"I don't think words can really describe your Major League debut, especially being a starter," Archer said. "I got drafted in 2006 and it's been a dream of mine since I was real small to do this. I know only a small percentage of people get to do it, and I'm going to make the most of it."
Hellickson heads to the DL with a 4-3 record, a 3.45 ERA, 52 strikeouts and 30 walks in 78 1/3 innings.
The right-hander endured his shortest outing of the season his last time out, working 3 2/3 innings Thursday against the Mets. He allowed a season-high eight runs on nine hits, including three home runs.
The poor start followed a 4 1/3-inning effort against the Marlins on June 8 in which Hellickson issued a season-high seven walks. Hellickson's lack of command against Miami and the poor start against the Mets stood as a significant departure from his previous effectiveness.
Hellickson worked at least six innings in eight of his first 11 starts, and he won four of his first six decisions.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.