Both players were assigned outright to the Minor Leagues and both elected to become free agents, the club announced on Wednesday.
Pena was with the Royals for four years, primarily as a backup catcher, and became an upbeat, smiling, hard-playing part of the team. In his Royals career, the switch-hitter played 264 games and batted .251 with 12 home runs, 41 doubles and 86 RBIs.
Volstad, a starter last year for the Cubs, was claimed off waivers on Oct. 26 by the Royals. A 6-foot-8 right-hander, he was coming off a 3-12 season in 21 starts for the Cubs and had a 6.31 ERA. Not good statistics but, at the time, the Royals were looking for starting pitching depth.
However, after the Royals traded for Ervin Santana and re-signed Jeremy Guthrie, the need for Volstad diminished. Both he and Pena were designated for assignment on Nov. 20.
During Spring Training this year Pena was the backup catcher for Salvador Perez -- until Perez suffered a knee injury and had to undergo surgery. With that, Pena's role increased and he split the catching with Humberto Quintero, who was obtained from the Astros.
With Perez's return in late June, however, Pena got little playing time. He was at peace with the backup role, however.
"I knew he was going to play a lot of games, I knew that from the get-go," he said.
Brett Hayes, claimed on waivers from the Marlins on Nov. 2, currently is the only other catcher besides Perez on the Royals' roster.
Pena was claimed on waivers by the Royals from the Braves on May 29, 2008, and spent the rest of that season with Triple-A Omaha. But he spent most of the next four years with Kansas City. A defector from Cuba as a teenager, he became a United States citizen while with the Royals.
"I had a great time with the Royals and my teammates. I loved the fans, I loved the city," Pena said. "I respected my coaches, every single one that I worked with. I feel like I was ready to do whatever it took to stay there, but I guess it didn't work out for them."
Known as a good hitter, Pena spent a lot of time improving his defensive skills, and he credited John Gibbons and Chino Cadahia, the Royals' last two bench and catching coaches, with helping him immensely.
Royals general manager Dayton Moore, who was an executive with the Braves during Pena's time with them, brought him to KC.
"I know that guy has stood up for me a lot of times," Pena said. "Maybe some people didn't want me there, but he got my back and he fought for me and I'm very thankful for that. That's something I'll never forget."
Pena was on a cruise last week with his family so he didn't know right away that he had been designated for assignment.
"I was very shocked when I heard the news," he said. "I found out the news through Internet. ... I was ready to take a pay cut to stay there. It's not about the money for me. It's about the chemistry, my teammates and city -- we loved it there."
Now, however, his KC days apparently are behind him.
"I know there's a lot of baseball left in me," said Pena, who is 30. "I feel good, I'm in great shape. I'm working out this offseason and I'm in the best shape I've ever been in my entire life. But that's the way it is. I'm not happy, but maybe it's time for me to move on."
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.