Wily Mo Pena was acquired in a trade with the Reds for Bronson Arroyo. Mistakenly believing that they had too much pitching, GM Theo Epstein decided he needed some outfield depth and acquired the power-hitting outfielder who hit 19 home runs the prior year and 26 the year before that in part-time work.
Pena actually had a decent year in 2006, although he was hurt a lot and was otherwise a part-time player. He hit .301/.349/.489/.838 with 11 home runs. He played right field and center field most of the time, while also playing in left field and designated hitter. He did show a tendency toward laziness in the outfield and did not walk much though. I saw him in two games that year and in the game in Kansas City, he hit a ball that landed on the roof of the concession stand out in left field, the longest home run I have ever seen.
The next year, Pena had even more injury problems and did not hit when he was in the lineup. He was traded to Washington near the end of the year for Chris Carter who was later traded in the Billy Wagner trade.