A lawyer with ties to a development firm that is trying to lure the FBI headquarters to a site near the Greenbelt Metro station is being considered for a seat on the transit agency’s board of directors.

Mark Winston, who lives in Potomac, was recommended by Montgomery County Executive Isiah Leggett (D) to replace Michael Barnes, a former congressman. Barnes has served on the Metro board since April 2011, and his term expires at the end of May. He said he is stepping down to serve on the board of a congressional ethics agency.

Winston is one of several candidates under consideration to replace Barnes on the 16-member Metro board, according to the Maryland governor’s office. Maryland, Virginia, the District and the federal government each have two voting members and two nonvoting members on the Metro board.

In an interview, Winston said he has an interest in KS Greenbelt, which has a minority interest in Renard Development of Greenbelt. Renard has an agreement with Metro to develop land near the Greenbelt Metro stop.

“I have a minority interest in a company that has a minority interest in Renard,” Winston said. “I have no authority in the chain of command at Renard.”

Winston said he has a “2.1 percent interest in the proceeds that Renard may enjoy from its contract with [Metro]” on the Greenbelt deal.

Winston’s candidacy comes as Metro implements a new ethics policy for its board of directors that requires more disclosure of personal finances and business interests. Under the new policy, Metro board members who have more than a 3 percent interest in a company that does business with the transit agency must recuse themselves from “any matter” that may present a conflict of interest.

D.C. Council member Jim Graham (D-Ward 1), who served on the Metro board until 2010, has been under scrutiny in connection with a development project. In October, an independent investigation ordered by the board concluded that Graham violated the transit agency’s ethics rules by improperly mixing his responsibilities as a Metro board member and a D.C. Council member.

The investigation concluded that Graham, in 2008, had promised members of Banneker Ventures that he would support Banneker’s bid for a contract to run the D.C. Lottery if the firm dropped out of a competition to develop Metro-owned property near the Shaw-Howard U Street stop.

Some Maryland and Virginia transportation officials and Metro staff members have raised questions about Winston’s connections to Renard because the Greenbelt property is competing against other sites — including one in Fairfax County near the Franconia-Springfield Metro stop — for the FBI headquarters.

But Montgomery County Attorney Marc Hansen said that, after reviewing Metro’s ethics policy and checking with the transit agency’s general counsel, he thought that Winston could serve on the Metro board.

Winston, 63, said that he “believes in the work” done by Metro and that “it is vital to the region.” He said he is interested in looking at how Metro and other transit agencies in the region can implement a “seamless” pay system for riders that involves using bank cards. Winston said he “frequently uses Metro to go to meetings downtown and in Rockville.” He said that he rides Metrobus but that “it has been a while.”

Winston has been active in civic affairs. He has served on several housing commissions, and he chaired a task force on how to establish a bus rapid transit system in Montgomery County. He has also served on the Maryland State Transportation Commission.

In 2006, Winston gave $500 to Leggett’s campaign, according to campaign finance reports.

Magda Jean-Louis and Jonathan O’Connell contributed to this report.