The Nationals have placed outfielder Wily Mo Pena on waivers, and decided to keep the contract of first baseman Dmitri Young. Opposing teams have three days to claim Pena and pick up his $2 million salary. If not, Washington could outright him to Triple-A Syracuse or he could ask for his release. "I think he needs to go down there to get his everyday at-bats and reps in the outfield," assistant general manager Mike Rizzo said. "He needs to prove, not only to the Nationals but 29 other clubs, that he is a viable Major League force."