(CNN) John Hickenlooper, who has struggled to break through the crowded Democratic presidential field, spoke to Senate Minority Leader Chuck Schumer late last week about running for the Senate from Colorado, a race he has resisted joining but is keeping an open mind about, a top aide tells CNN.

"He is still in the race for president, but he hasn't closed the door to anything," said Peter Cunningham, the communications director for the former Colorado governor.

The latest conversation between Hickenlooper and Schumer took place in New York, following the CNN presidential debates in Detroit. The two have spoken repeatedly about the Senate contest, but Hickenlooper has been insistent on keeping his presidential campaign alive.

Yet Hickenlooper is also facing the reality of not making the next debate in September, according to people familiar with his campaign operation. He is well behind in the number of donors and level of polling needed to qualify, they said.

Hickenlooper, a former Denver mayor, is in Iowa this week, pressing ahead with his presidential campaign schedule. He has told friends that he believes he is what the party needs as a presidential nominee, but has also acknowledged that his message has failed to gain traction.

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