Penn has been placed on Triple-A Indianapolis' temporary inactive list.
It was the Marines that made the initial inquiry about Penn, and when the right-hander found out about the club's interest through his agent, he made it clear to Pittsburgh that he wanted the chance to go. The Pirates, who had the option of refusing Penn's request, instead reluctantly agreed.
"The money was such that he felt it was important for him to be allowed this opportunity," Huntington said. "Part of us wanted to say, 'No.' But as we look forward to the 2011 club, while there were some things that we were really intrigued by, it was tough to stand in this young man's way. He felt like this was a tremendous opportunity for him."
Though Penn was putting together a decent season down in Indianapolis, he is not atop the organization's Minor League depth chart. Furthermore, the fact that Penn has no Minor League options meant that if he didn't make the team out of Spring Training next year, Penn could be lost anyway.
Penn began the season in Pittsburgh, though that stay lasted a brief 2 1/3 innings. Penn allowed eight runs on eight hits and three walks in those three games. Working as a starter in Triple-A, Penn went 4-4 with a 4.68 ERA, 56 strikeouts and 23 walks in 65 1/3 innings. He was named Indianapolis' pitcher of the month after posting a 1.89 ERA in six starts.
The Pirates are also currently in discussions with another Japanese club that has interest in Triple-A reliever Vinnie Chulk. Those talks are ongoing, though Chulk, too, has been placed on the inactive list.