"He's throwing the ball well," Padres manager Bud Black said. "I think he's gaining confidence. He's pitching with more conviction with his pitches. I think early on he was a little tentative, but now he's settled in."
Black added that Quackenbush drew a lot of praise from his Minor League coaches after posting a 1.26 ERA in 14 1/3 innings pitched and converting all six of his save chances for Triple-A El Paso early this season.
Still, Quackenbush remains a candidate to be sent back down to the Minors as the Padres plan to call a pitcher up to start on Saturday.
"When we activate a pitcher on Saturday, it's going to be a tough move for someone," Black said.
Erik Bacharach is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.