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.
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.