Barajas will make $4 million in 2012 and the club holds a $3.5 million option for the 2013 season. If Barajas is traded, it becomes a mutual option. The 36-year-old hit .230 with 16 home runs and 47 RBIs last season while playing for the Los Angeles Dodgers.
"They were aggressive," Barajas said. "They gave me the feeling they really wanted me to be a part of their team. They played good baseball for four months last season and showed a lot of improvement. I thought this would be a good situation to be in."
Barajas is one of the top power-hitting catchers in the game. He hit 33 homers the past two seasons.
"He has the combination of attributes we're looking for, an experienced catcher with the willingness to help improve a young pitching staff and he also adds some power to the lineup," Pittsburgh general manager Neal Huntington said.
Barajas, a career .238 hitter, has 125 home runs and 449 RBIs in 1,010 career games with Arizona, Texas, Toronto, Philadelphia, the New York Mets and the Dodgers.