House Speaker Michael E. Busch. (Photo by Marvin Joseph/The Washington Post)

Maryland Lt. Gov. Anthony G. Brown (D) is scheduled to pick up his latest endorsement for governor this week from House Speaker Michael E. Busch, who rarely endorses in Democratic primaries, according to two people familiar with the arrangement.

Brown has credited Busch (D-Anne Arundel) with being a mentor during his days in the House of Delegates. In 2004, Busch elevated Brown, then a second-term member from Prince George’s County, to majority whip — a leadership position that facilitated Brown’s rapid rise in Maryland politics.

The following year, then-Baltimore Mayor Martin O’Malley (D) tapped Brown for the No. 2 spot on his 2006 gubernatorial ticket.

Busch plans to announce his support of Brown’s 2014 gubernatorial bid on Thursday, according to the two people, who requested anonymity because they are not authorized to speak on behalf of the Brown campaign or Busch.

Aides to both Brown and Busch declined to comment on Monday.

Brown faces Attorney General Douglas F. Gansler (D) and Del. Heather R. Mizeur (D-Montgomery) in the June Democratic primary for governor.

Brown has racked up far more endorsements from fellow Democrats than either of his competitors. His supporters include O’Malley, Sen. Barbara A. Mikulski (D-Md.), House Minority Whip Steny H. Hoyer (D-Md.) and state Senate President Thomas V. Mike Miller Jr. (D-Calvert).

Gansler has been dismissive of the endorsements collected by Brown, telling audiences that voters will decide the race.

“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 at recent forum hosted by a labor group.