PORTLAND – The Boston Red Sox and Portland Sea Dogs have announced the extension of their player development contract for an additional four years, through the 2012 season.

Red Sox Vice President of Player Personnel Ben Cherington and Sea Dogs President and General Manager Charlie Eshbach made the announcement Monday afternoon at Hadlock Field.

“The most important ingredient in an affiliate are the people involved,” said Cherington in a press release from the Sea Dogs, “and we are very fortunate to work with some of the best people in minor league baseball here in Portland. [Owner] Dan Burke, Charlie Eshbach, and the entire Sea Dogs staff have consistently gone the extra mile to provide support to our players and staff over the last 41/2 years. This support translates to performance on the field over the course of a long minor league season.

“The planned clubhouse improvements will make Portland an upper echelon Double-A facility, benefiting our players and staff for years to come.”

The Sea Dogs began their relationship with the Boston Red Sox on Sept. 18, 2002, after nine years with the Florida Marlins. The Sea Dogs and Red Sox originally entered into a two-year player development contract that ran through the 2004 season.

On May 14, 2004, the Sea Dogs and Red Sox announced a four-year extension keeping the Red Sox in Portland through the 2008 season. Player development contracts can extend in either two- or four-year increments. A four-year extension is the longest permissible.

“We are thrilled with the extension of the PDC with the Boston Red Sox,” said Eshbach in the same release. “When we joined with the Red Sox in September 2002, it was with the intention of establishing a long-term relationship. The extension of the PDC for an additional four years helps to further strengthen that bond.”

Former Sea Dogs now with the Red Sox include Josh Beckett, Manny Delcarmen, Jacoby Ellsbury, Kason Gabbard, Jonathan Papelbon, Dustin Pedroia and Kevin Youkilis. In all, 29 players have made the move from Hadlock Field to Fenway Park.

The switch in affiliation to a team with countless loyalists in Maine was widely applauded by Sea Dogs fans, who turned out in record numbers during each season that the partnership has been in place.

The minor league team had marked the change by building a likeness of Fenway Park’s Green Monster in left field and renaming the skyboxes at Hadlock Field in honor of former Red Sox batting stars.

Last season, the Sea Dogs won their first Eastern League championship in the 13-year history of the franchise.

4 Sea Dogs named EL all-stars

Four Portland Sea Dogs have been selected to participate in the Eastern League All-Star Game on July 11 at Dodd Stadium in Norwich, Conn.

The four Sea Dogs are pitchers Clay Buchholz and Charlie Zink, shortstop Jed Lowrie, and outfielder Jeff Corsaletti.

The All-Star game will feature the Northern Division against the Southern Division. Each team will consist of 24 players.

The All-Star teams were selected through fan balloting along with selections from media personnel, club field personnel, and league administrators. Each Eastern League team is represented by at least three players, including at least one pitcher and one position player.

Red Sox top pitching prospect Buchholz leads the league in ERA (1.69) and strikeouts (115). His 115 strikeouts are the most in all of minor league baseball. The Lumberton, Texas, native has a 6-2 record in 15 starts.

Zink leads the Sea Dogs with eight wins, which ranks second in the Eastern League. In 11 starts he has an 8-2 record with a 2.59 ERA, which ranks third in the league.

Shortstop Lowrie has appeared in a team-high 71 games and leads the team with a .295 average. He’s tied for the Eastern League lead in walks (48), second in triples (7), and fourth in doubles (22).

Outfielder Corsaletti holds a .285 average in 69 games. He’s fifth in the league with 53 runs scored and leads the Sea Dogs with 11 stolen bases.