Youkilis gave up his first two years of free agency, and possibly a third if the option is exercised.
When Pedroia signed his contract last month, Red Sox general manager Theo Epstein said that part of the club's policy on extensions with its younger players is that at least one free-agent year is relinquished.
The terms of the contract are as follows: Youkilis, who will receive a $1 million signing bonus, will earn $6 million in 2009. He will make $10 million in 2010, $12 million in 2011 and 2012. The club option for 2013 is for $14 million, and includes a $1.25 million buyout.
Youkilis was solid in his first two seasons as an everyday player, but turned into a star in 2008. In 145 games, Youkilis hit .312 with 29 homers, 115 RBIs and a .569 slugging percentage. He finished third in the MVP voting, trailing only Pedroia and the Twins' Justin Morneau.
Yet another solid performer who came up through the Boston farm system, Youkilis was drafted by the Red Sox out the University of Cincinnati in 2001.
He made his debut with the Red Sox in 2004, roving back and forth between Boston and Triple-A Pawtucket for two seasons.
In 2006, Youkilis, who came up through the Minor Leagues as a third baseman, made a seamless transition to the other side of the diamond to become Boston's first baseman.
In fact, Youkilis has become of the best defensive players in the league at that position, as evidenced by the Gold Glove he won in 2007.
Part of the beauty of Youkilis is that he can still play a very solid third base, and never balks at doing so when Mike Lowell is either injured or given a breather. Youkilis started all seven games at third base in last October's American League Championship Series.
Manager Terry Francona has also come to embrace the adaptability of Youkilis to hit in any part of the batting order.
After superstar slugger Manny Ramirez was traded to the Dodgers on July 31, Youkilis moved to the cleanup spot and put up strong numbers.
The past two Octobers, Youkilis has proved that he is a clutch player, hitting .333 with six homers and 19 RBIs in 99 postseason at-bats.