The four-year deal is worth $18.25 million US with a $1-million signing bonus.
Bay, a 27-year-old outfielder from Trail, B.C., will earn $750,000 next year, $3.25 million in 2007, $5.75 million in 2008 and $7.5 million in 2009.
"This is one of the best days of my life," said Bay. "But I'm glad this is over. This is an experience I will never forget."
Jason Bay was an NL all-star in 2005. (AP Photo/Al Behrman)
The length of the deal is noteworthy because it covers his arbitration-eligible seasons. Bay was not eligible for arbitration until after next season and could not become a free agent until after 2009.
He made $355,000 last season after he couldn't come to terms with the team and have his contract automatically renewed.
Bay was named National League rookie of the year in 2004 and followed that up this season by hitting .306 with 32 home runs, 101 runs batted in, 110 runs scored, 21 stolen bases and a .402 on-base percentage.
He finished 12th in voting for most valuable player in the NL this year.
"It's spectacular what he's done so far in the big leagues," Pirates general manager Dave Littlefield said. "I don't have any doubts he will continue to improve throughout his career."
In 2004, Bay hit .282 with 26 HRs and 82 RBIs in 120 games to become the first Rookie of the Year in Pirates history.
He isn't worried about any added pressure that is associated with signing a big contract.
"I've been dealing with the pressure since I got drafted – a 22nd round draft pick (by the Montreal Expos in 2000)," Bay said. "I felt pressure coming here in a big trade – Brian Giles, how are you can follow that up? I handled that and won Rookie of the Year. Boom, then it's the sophomore slump, what's going to happen there?
"But I've said a million times, I'm not out to prove anybody wrong, or stick it to anybody, but I'm more out to prove to myself I can do this."
Bay was traded to the New York Mets on March 26, 2002.
The San Diego Padres acquired Bay later that year before shipping him along with Oliver Perez and a player to be named later to Pittsburgh for Giles on Aug. 23, 2003.
with files from Associated Press and Sports Network
