"Our bullpen's been pushed too hard lately," said Padres skipper Andy Green. "We've had a number of starts that haven't gone too deep in the game. We just got to the point where we needed an extra arm. We needed coverage, and we thought Michael Kirkman gives us that coverage."
In parts of five big league seasons with Texas, Kirkman has posted a 4.98 ERA and a 1.453 WHIP. He had allowed three earned runs on three hits in six innings for El Paso.
The Padres haven't told Kirkman specifically what role he'll fill, but he's done a little bit of everything in the past -- matchups, long relief and one-inning appearances.
"I'll just be ready whenever the time comes -- probably the middle innings," Kirkman said. "I'll be ready when they call my name."
Kirkman signed his Minor League deal with the Padres during the offseason. He said it was the only offer he received. As for his pitching philosophy, Kirkman is known as a soft-contact guy who tries to keep the ball on the ground.
"Keep the ball down, sink it, slide it," he said.
Kirkman seemed legitimately surprised he received the phone call around 9:30 Tuesday morning. He hasn't pitched in the big leagues since 2014 with Texas and wasn't on the 40-man roster.
"I had no idea that they were contemplating the move," Kirkman said. "It's one of those things where I'm just happy to be here."
Pirela will continue to receive reps at second base for El Paso. Mazzoni, meanwhile, must clear waivers to be outrighted to Triple-A.
With Kirkman's arrival, the Padres will play with a four-man bench and an eight-man bullpen for the first time this season.
"It doesn't allow for the versatility ... but sometimes you have to do it in order to protect your arms," Green said.
AJ Cassavell covers the Padres for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.