"Our scouts still saw the hitting abilities that made Ryan a successful hitter," Huntington said. "There's every reason to believe he's going to be a more productive hitter than his surface-level numbers indicate.
Now in his ninth big league season, the right-handed hitting Ludwick made his Major League debut with the Texas Rangers in 2002. He has also seen action with Cleveland (2003-05) and St. Louis (2007- 2010) before being traded to San Diego last year on July 31.
"This is a lot like last year," Ludwick said. "The only difference is, I've been hearing from day one, even in spring training, that I was a possible (trade) piece. It seemed every time I looked, teams were inquiring about me."
In 752 career games, Ludwick has compiled a .262 batting average, 115 homers and 439 RBI.
To make room on the 40-man roster, the Pirates have designated RHP Mike Crotta for assignment.
"Pittsburgh is a good fit for me," Ludwick said. "I've fared pretty well in (PNC Park) and I'm familiar with the Central. And I'm excited to be going to a team in a pennant race."