Happ pitched two-thirds of an inning Wednesday in a 9-2 loss to the Dodgers at Citizens Bank Park. Happ could have pitched longer, but Manuel needed to save him for Saturday.
"He was the most logical guy," Manuel said. "We put him in there to get his work in."
Happ, who lost the competition for the fifth spot in the rotation during Spring Training to Chan Ho Park, is 1-0 with a 2.84 ERA in 10 appearances.
If Happ pitches well Saturday, could that improve his chances of getting back into the rotation?
"Somewhere down the line if we have to make adjustments, of course there could be a place there for Happ," Manuel said. "But is this one game going to make or break him as far as being a starter on our staff? I don't think so."
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.