GOP gubernatorial hopeful David R. Craig makes a stop in Dundalk last month.(Photo by Mark Gail/For The Washington Post)

Maryland 2014 Republican gubernatorial contender David R. Craig on Tuesday plans to unveil Del. Jeannie Haddaway-Riccio (R-Talbot) as his running mate, according to several people familiar with the pick.

As the lieutenant governor candidate, Haddaway-Riccio, a former House minority whip, will add both generational and gender balance to the ticket. Craig, the current Harford County executive, is 64; Haddaway-Riccio, who is well-regarded among members of both parties in the House of Delegates, is 36.

Jim Pettit, a Craig spokesman, confirmed the campaign’s plans to announce a running mate Tuesday but declined to comment on the pick. Haddaway-Riccio did not immediately return a phone call. The sources who spoke about her selection requested anonymity because they are not authorized to speak for the campaign.

The expected announcement is the latest instance of a candidate seeking to get an early start on next year’s race to succeed Gov. Martin O’Malley (D).

Lt. Gov. Anthony G. Brown, a leading Democratic contender, announced his running mate — Howard County Executive Ken Ulman (D) — in June, about a month after entering the race himself.

Craig announced his candidacy for the GOP nomination on the same day in early June.

One other Republican — Del. Ronald A. George (R-Anne Arundel) — has also announced his candidacy. Several others, including former Republican National Committee Chairman Michael S. Steele, are considering joining the race.

Haddaway-Riccio, an Easton native, was appointed to the House in 2003. She ascended to minority whip, the No. 2 position in the House GOP caucus, in 2011. Haddaway-Riccio lost that position in a leadership shake-up in April.