A Suffolk University/ USA TODAY poll released Monday places Pete Buttigieg in third place in Iowa behind former Vice President Joe Biden and Massachusetts Senator Elizabeth Warren.

Pollsters surveyed 500 likely Democratic caucusgoers.

The poll put Buttigieg, the openly gay mayor of South Bend, Indiana, at 13 percent, behind Biden (18%) and Warren (17%).

No other Democratic presidential candidate polled above 10 percent.

David Paleologos, director of the Suffolk Political Research Center, said that the poll's results show that “Iowa is unquestionably up for grabs.”

“[Buttigieg] has found a lane and is accelerating toward the front of the pack, surpassing Bernie Sanders. All of this is happening while the number of undecided voters continues to grow as Democratic caucusgoers pause to reevaluate the changing field,” he said.

(Related: Pete Buttigieg: America is ready for a gay president.)

The Iowa caucuses, the first major contest of the U.S. presidential primary season, take place on February 3, 2020.