Rep. John P. Sarbanes (D-Md.) on Monday became the latest Democratic officeholder to endorse the 2014 gubernatorial bid of Lt. Gov. Anthony G. Brown (D), whom he called “a proven and resourceful leader.”

“I have had the pleasure of working with Lieutenant Governor Brown on a variety of initiatives, including the effort to implement health care reform in our state and to ensure that the Baltimore region is maximizing the opportunities presented by BRAC,” Sarbanes said in a statement, referring to the military’s base realignment and closure process.

The backing of Sarbanes, whose district includes mostly Baltimore-area counties, was announced a day before Brown’s chief rival, Attorney General Douglas F. Gansler (D), plans to formally kick off his campaign in Rockville.

Gansler, who plans a 17-stop announcement tour, has been dismissive of a string of endorsements collected by Brown, who announced his candidacy in May.

“Up to this point, it’s been sort of the establishment and the machine against the people of Maryland, the real people, and real ideas,” Gansler said Monday during an appearance in Ellicott City before a gathering of the Maryland State and Washington, D.C. Building and Construction Trades Council, a labor group.

A third Democrat, Del. Heather R. Mizeur (D-Montgomery), is also in the race.

Sarbanes is the fifth member of Maryland’s congressional delegation to back Brown. Others include Sen. Barbara A. Mikulski, who announced her backing Sunday; House Minority Whip Steny H. Hoyer; Rep. Elijah Cummings; and Rep. Donna F. Edwards.

Brown has also picked up endorsements from Gov. Martin O’Malley (D), Senate President Thomas V. Mike Miller Jr. (D) and Baltimore Mayor Stephanie Rawlings-Blake (D).

Sarbanes, who was first elected in 2007, represents a district that includes parts of Baltimore City and Anne Arundel, Baltimore, Howard and Montgomery counties.