Penn split the 2009 season with Florida and Triple-A New Orleans after being acquired by the Marlins from Baltimore on April 1 in exchange for infielder Robert Andino. The 25-year-old righthander was a member of Florida's Opening Day roster in 2009 and went 1-0 in 16 appearances (one start) with the Marlins. In addition, Penn went 2-4 in 14 games (13 starts) with New Orleans.
Pirates GM Neal Huntington has had Penn on his radar for some time.
"When you hear that kind of stuff, you always wonder, 'Are they serious or are they just saying it?'" said Penn. "I talked with Neal (on Monday), and he said they had interest before, so I'm glad to be here."
Penn will have a small window of opportunity with the Pirates because no options remain on his contract, he would have to clear waivers before he was sent to the minor leagues.
"We plan to have him throw on Thursday and Saturday (in preseason games), and we'll make a decision from there," Huntington said. "Whether we keep 11 (pitchers) or 12, who be the final one or two people is something that we'll have to decide this weekend."
Penn knows he is under the gun to make an impression.
"It's the same game," he said. "I'll go out there and do everything that I can (to earn a roster spot). If I'm on my game, then I'll show them what I need to show them. If I don't, then I won't. It's as simple as that."
Penn struggled in five spring outings with the Marlins and had an 8.81 ERA.
"I struggled a little bit in the last two outings, but my first part of spring was pretty good," he said. "I got thrown out of rotation starting and reliving, but I felt good health-wise. I'm ready to go."