Oberholtzer, who was told of the decision following Saturday's game, went 2-0 with a 2.08 ERA in two starts since being called back up on May 24. He needed only 81 pitches Friday to throw seven innings to beat Baltimore.
"It was a tough one, when you look at how well Obie pitched his two outings," manager Bo Porter said. "At the same time, you can only have 25 guys, and looking at the fact we have an off-day [Monday], we didn't want to stay on the six-man rotation, because now these guys are pitching once a week. We didn't see that as something we wanted to do."
Astros starters have posted a 3.05 ERA in 26 games since May 5, with 18 quality starts in that span. Oberholtzer came up to give the starters an extra day of rest while they gave Brad Peacock some time to deal with a sore forearm. Oberholtzer will stay on turn for Oklahoma City.
"It's a unique situation that we haven't found ourselves in the last couple of years, where we have six quality guys," general manager Jeff Luhnow said. "When we have a lot of games in a row, we could probably do a six-man rotation like we just did. We have an off-day Monday, and we have a couple of more off-days in June, and it's difficult to have a six-man rotation, because with the extra day, you're essentially asking them to pitch once a week a couple of times through the month, and that's hard, because you start to lose your rhythm at that point."
Clemens is no stranger to making the trip between Houston and Oklahoma City, having bounced between the two clubs several times since the start of last year. Clemens is 0-1 with a 4.08 ERA in eight games with the Astros this year.
"I've learned a ton the last couple of years just about baseball and the world up here, so I am definitely more prepared for a lot of things that have been thrown at me this year as opposed to years past," he said. "I think that's big time. I've come a long way in terms of being able to handle these sorts of things and take it in stride. I know deep down what my arm's capable of, and these are little bumps along the way."
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.