Gonzalez has been a favorite for years and San Diegans are sad to see him go.
"I think it is horrible, I think he is the greatest player we have ever had here in San Diego," said Chris Lynskey, a longtime Padres fan. "He is a local boy. It is going to be the greatest loss to the Padres organization in a long long time."
The Padres, who have a long history of dumping star players due to financial reasons, will receive three of Boston's top prospects, plus a player to be determined in exchange for Gonzalez.
San Diego's ability to keep star players has been stunted by the size of their wallet. Teams like the Red Sox have deeper pockets and the ability to pay for top talent. Many San Diego fans realize this and don't blame Gonzalez for leaving.
"It's not a done deal, they still have to sign him to a multi-year contract," said Bill Bow commented on NBC's Facebook page. "Hate to see him go, but he deserves the big bucks for his dedication and hard work. A real class act."
All-Star slugger Adrian Gonzalez was in Boston on Saturday to take a physical exam needed to complete a trade from the San Diego Padres to the Red Sox, two people familiar with the situation told The Associated Press. The people spoke on condition of anonymity because the trade hasn't been finalized.
Gonzalez had surgery to clean up the labrum in his non-throwing right shoulder on Oct. 20. The Padres said then that the three-time All-Star and two-time Gold Glove Award-winning first baseman was expected to be ready for spring training.
Besides passing the physical, Gonzalez and the Red Sox will have to agree to a renegotiated contract because of the caliber of prospects Boston is giving up, one of the people familiar with the deal said. That person said the teams hope to wrap up the trade before the winter meetings start Monday.
Boston plans to trade right-hander Casey Kelly, first baseman Anthony Rizzo and outfielder Reymond Fuentes for Gonzalez.
Rizzo is probably two years away from the big leagues, so the Padres will have to sign a free agent to play the position to begin the season. Kyle Blanks, a first baseman who had been switched to left field to give him playing time, had reconstructive surgery on his right elbow in late July and is expected to be sidelined until perhaps midseason.
Red Sox general manager Theo Epstein did not respond to an e-mail seeking confirmation. Padres GM Jed Hoyer hasn't responded to requests for comment.
Hoyer worked under Epstein in Boston's front office before he was hired as Padres GM following the 2009 season. Additionally, Padres assistant GM Jason McLeod was Boston's scouting director for seven years before returning to San Diego last December. McLeod drafted Kelly, Rizzo and Fuentes.
The popular Gonzalez grew up in the San Diego area and was the No. 1 overall pick by Florida in the 2000 amateur draft. He was obtained in a trade with Texas before the 2006 season and has blossomed into one of the game's best first basemen. The left-hander hit .298 with 31 homers and 101 RBIs last season.
Boston was interested in Gonzalez last winter.
While many had expected Gonzalez to be traded before the deadline last summer, the Padres were surprise contenders in the NL West and had to keep the slugger.
The Padres went 90-72 despite opening the season with a payroll of $37.8 million, second-lowest in the majors. San Diego was in contention until the final day, when its loss at San Francisco, coupled with Atlanta's win over Philadelphia, eliminated the Padres from the NL West and wild-card races.
Hoyer has said for some time that the Padres wouldn't be able to afford the kind of big-money contract Gonzalez would command if he hit the free-agent market.
Hoyer also has said he anticipated Gonzalez being on the opening-day roster. But the allure of prospects is probably too much to pass up for a team that anticipates a player payroll of approximately $40 million.
The Padres recently exercised Gonzalez's $6.2 million option for 2011, the final year of a team-friendly $15 million, five-year contract he signed in 2007.
In five seasons with San Diego, Gonzalez has 161 homers -- two shy of Nate Colbert's club record -- and 501 RBIs. Including parts of two seasons with Texas, he has 168 homers and 525 RBIs.
He set a Padres record with his fourth 30-homer season. His third 100-RBI season tied Phil Nevin for the most in club history.
The Padres already have lost right-hander Jon Garland, shortstop Miguel Tejada and catcher Yorvit Torrealba to free agency, and won't re-sign outfielders Scott Hairston and Tony Gwynn Jr. They also declined to pick up right-hander Chris Young's $8.5 million option.
In a salary purge that lasted from September 1992 to July 1993, the Padres traded All-Stars Fred McGriff, Gary Sheffield and Tony Fernandez, and let Randy Myers and All-Star Benito Santiago leave via free agency. They also traded Craig Lefferts, Bruce Hurst, Greg Harris and Darrin Jackson.
After being swept by the New York Yankees in the 1998 World Series, they let Kevin Brown, Ken Caminiti and Steve Finley leave as free agents and traded Greg Vaughn.
Less than two weeks after that World Series ended, voters overwhelmingly approved Petco Park, which was supposed to have provided the revenue to make the Padres consistent contenders. San Diego won the NL West in 2005-06, but has won only one postseason game since 1998.