The Boston Red Sox appear to have finally acquired San Diego Padres first baseman Adrian Gonzalez

Sources have told ESPN The Magazine‘s Buster Olney this morning that the Red Sox and Padres have reached an agreement to trade Gonzalez to Boston in exchange for several top prospects.

The next phase of the deal is a contract extension for Gonzalez, who is only signed through next season for about $6 million.

Gonzalez has been flown to Boston by the Red Sox and will attempt to work out a contract extension with general manager Theo Epstein.

According to baseball experts, Gonzalez will be looking for a contract similar to what the New York Yankees gave Mark Teixeira before the 2009 season (eight years, $160 million).

According to ESPNBoston.com’s Gordon Edes, the Padres will receive Red Sox pitcher Casey Kelly, first baseman Anthony Rizzo and outfielder Reymond Fuentes.

Kelly, 21, is the top prospect in the Red Sox organization, according to Baseball America, and has been considered as a primary chip to acquire any big-name player like Gonzalez.

Rizzo, 21, hit 20 home runs with 80 RBIs last season with Boston’s Double-A affiliate Portland. Fuentes, who is only 19 years old, was the Red Sox top draft pick in 2009, and stole 42 bases for Single-A Greenville last season. 

Gonzalez has hit at least 30 home runs and driven at least 99 RBIs each of the last four seasons. His defensive ability is stellar as well, and in five full seasons, Gonzalez has won two Gold Gloves.

The Red Sox had to make a splash, either with a trade or big free-agent signing this winter. Boston failed to make the playoffs in 2010, and has already let star catcher Victor Martinez sign with Detroit as a free agent.

Adrian Beltre, the Red Sox MVP of 2010, is also a free agent, and is now unlikely to re-sign with Gonzalez arriving.

Now that the Red Sox have their man, they can focus on building a better bullpen, their most glaring weakness from last season.

Epstein has been trying to acquire Gonzalez since the 2009 trade deadline, and it now looks like the slugger will finally be a Red Sox player in 2011.

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