"We felt like we needed another left-hander," Rangers manager Ron Washington said.
Poreda, who was called up after Tanner Scheppers went on the disabled list Friday, pitched in five games at Triple-A Round Rock. He allowed three runs in one game but there other four were scoreless outings, including the last three.
"He was throwing the ball well," Washington said. "He has good velocity and has an idea of how to pitch."
Poreda is in the big leagues for the first time since 2009, when he appeared in four games with the Padres. He previously appeared in 10 games for the White Sox that season, before being one of four players traded to the Padres for Jake Peavy at the July 31 Trade Deadline.
Poreda, who was the White Sox's first pick in the 2007 First-Year Player Draft, missed all of last season after undergoing Tommy John elbow reconstruction surgery in October 2012. He signed with the Rangers as a Minor League free agent in the offseason.
"It's awesome, I'm excited to be here," Poreda said. "This is definitely a second opportunity for me and I'm going to make the most of it and be the best I can be. I'm ready for anything and everything."
The Rangers decided against calling up Neftali Feliz, who has a 1.59 ERA in five appearances at Round Rock. They still want him to work on a number of things, including his endurance, stamina and mechanics.
"We talked about that," general manager Jon Daniels said. "We feel like he's close. Kind of like we talked about in spring training, we really want to make sure he's ready."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.