Public Advocate Jumaane Williams cracked the door open to a possible mayoral bid Tuesday during an hour-long debate as he campaigns for reelection — but said he would only consider it down the road.

“I’m not running for mayor in 2021 and I actually have no plans to do so, but it’s hard to say never in these things,” Williams said during the NY1 forum with his Republican challenger, Councilman Joe Borelli.

It’s a change in tone for Williams, who denied any interest in seeking Gracie Mansion when he ran and won the special election for Public Advocate in February.

At one point, Williams opted to sit on the ground to emphasis his disinterest in the position when the moderator at a January 31 forum asked the candidates if they planned to run for mayor. His move won laughs from the audience.

Williams is heavily favored to keep the citywide post, which commands an outsized profile compared to its tiny $3.5 million budget.

The election for public advocate is set for November 5.