A three-way race for the 66 delegates up for grabs in the Ohio Republican Presidential Primary is developing, and Sen. Marco Rubio is on the outside of that race looking in.

An Ohio Primary poll published Tuesday by Quinnipiac shows Donald Trump leading the way with 31 percent support, followed by home state Gov. John Kasich, with 26 percent. Kasich is trailed by Ted Cruz, holding 21 percent of supporters.

Sen. Marco Rubio (R-FL) is a distant fourth in Ohio. He sits at 13 percent. Dr. Ben Carson trails Rubio with only 5 percent of likely Ohio voters.

Some 38 percent of respondents said they would consider changing their mind before the March 15 Primary, while 5 percent are currently undecided.

Though Trump leads the way, he also leads on the negative side. A third of likely voters said they will “definitely not support” the businessman.

“The Donald Trump train begins the three-week campaign for Ohio’s crucial delegates on the right track and holds a small lead over the Buckeye State’s own governor, John Kasich,” said Peter A. Brown, the assistant director of the Quinnipiac University Poll, in a statement released with the survey. “A Kasich Ohio win is crucial to the Republicans trying to stop the New York businessman’s nomination. If Trump can defeat Kasich in his home state, that would be an impressive demonstration of his strength in a state that is just now getting attention.”

“But Trump’s lead is just 5 points, certainly not large enough for him to breathe easy,” he added.

On the Democratic side, Hillary Clinton maintains a comfortable lead, beating rival Sen. Bernie Sanders (I-VT) 55-40 percent.

The Quinnipiac poll surveyed 759 Ohio likely Republican primary voters with a margin of error of +/- 3.6 percent, and 518 Ohio likely Democratic primary voters with a margin of error of +/- 4.3 percent.