DENVER -- Denver Mayor John Hickenlooper has bowed out of the race for Colorado's last open superdelegate seat at the Democratic National Convention, giving Barack Obama an opportunity to pick up a vote.

Hickenlooper has been neutral, but the other major candidate for the superdelegate seat, former Mayor Federico Pena, is an Obama supporter.

State Party Chairwoman Pat Waak said there were four candidates for the open superdelegate position (Hickenlooper, House Speaker Andrew Romanoff, Lt. Gov. Barbara O'Brien, and Pena).

Hickenlooper, Romanoff and O'Briend have all withdrew their names, leaving Pena the likely superdelegate.

Other candidates could emerge before the seat is filled at the state Democratic convention on Saturday.

Waak announced Hickenlooper's decision Wednesday but did not give a reason.

The national convention will be in Denver in August.