Former Montgomery County Executive Doug Duncan is preparing a run for his old job in 2014, potentially setting up a high-stakes political battle in Maryland's largest county.

Duncan, who led Montgomery County from 1994 until he ran for governor in 2006, has discussed his plans with several Democratic supporters, but has made no official announcement. Duncan, who is 57, did not immediately return a call seeking comment.

Citing clinical depression, Duncan dropped out of the 2006 Democratic primary against then-Mayor Martin O’Malley. After a long hiatus from politics, the former Rockville mayor has been increasingly visible in the past year. He was an early and aggressive backer of John Delaney, the Potomac Democrat who unseated Republican Rep. Roscoe G. Bartlett earlier this month.

Duncan was a regular appearance at Delaney campaign events -- from press conferences to early-morning handshaking at Metro stops.

If Duncan runs he could face two-term Democratic incumbent Isiah "Ike" Leggett. Leggett, 67, had previously said he would not seek a third term, but has recently softened that position. A Duncan-Leggett contest could have statewide political implications, particularly if the Democratic gubernatorial candidates who will also be running in 2014 are drawn into the local race.

Duncan, who became known as the "Mayor of Montgomery," is widely credited with revitalizing downtown Silver Spring. Others note that the county has undergone significant population and demographic changes since Duncan left office, which would require him to introduce himself to many new voters.