Pena, who has played the last four seasons with the Rays, is a free agent, while Nieves is arbitration-eligible. There is a good chance Nieves will be non-tendered as the Nationals are set with Ivan Rodriguez and Wilson Ramos behind the plate.
"Hopefully we can play together in the big leagues," Nieves said via phone. "I think the people who will be happier are my wife and his wife, because they can be together all the time. That's like our dream. Only God knows what's going to happen.
"Carlos is open to anything. I told him that Washington is a great city and that the Nationals are going in the right direction. He can help Ian Desmond and Ryan Zimmerman when it comes to picking up their throws at first base."
Even if he doesn't go back to Washington, Nieves believes that Pena will be a good fit with the Nationals. The Nationals consider Pena their top candidate to play first base if they cannot sign Adam Dunn to a contract extension. Nieves said that Pena is aware that the Nationals are strongly thinking about acquiring his services.
"Carlos is a great person to have in the clubhouse," Nieves said. "He is really a positive guy. He is a great first baseman. He is unbelievable with the glove. He can hit, too, and bring some people home. He knows he can hit better than what he did. He still had his home runs and RBIs."
Pena had one of the worst seasons of his career, hitting .196 with 28 home runs and 84 RBIs this past season. Asked if injuries played a role in Pena's batting average, Nieves said Pena didn't use any excuses for his problems at the plate. In fact, Pena and Nieves are planning to work with Nationals hitting coach Rick Eckstein in January.
"Carlos doesn't blame his low [batting average] on anything," Nieves said. "He was working on stuff. He doesn't know what happened. He was feeling uncomfortable at the plate."
Nieves and Pena became best friends when they were in the Yankees' organization in 2006. They were teammates while playing for Triple-A Columbus before Pena went to the Red Sox in August of that year.
Since then, Pena and Nieves have become neighbors in Orlando, Fla., while Pena is the godfather of Nieves' daughter, Maria Isabel.
"We clicked. We talk about everything," Nieves said. "We see each other every day in Orlando. I'm learning how to play golf because he loves golf. So I'm trying to keep up with him. Every single year after the season is over, we do something together. We take a cruise or vacations. My wife and his wife are best friends. They talk on the phone every day for hours. His wife is a saint. She is a sweetheart."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.