Washington (CNN) Marco Rubio may be gone, but he's not all the way out.

State Republican Party chairmen in places where the Florida senator won delegates -- necessary to secure the party's presidential nomination -- say Rubio's campaign has contacted them saying he wants to hold on to that support for now.

His decision to try to keep his 173 delegates could make Donald Trump's path to the 1,237 needed to clinch the nomination just a little bit tougher.

"Of course, he's no longer a candidate and wants to give voters a chance to stop Trump," said Alex Burgos, a Rubio spokesman.

A source familiar with the strategy told CNN the move to hold on to delegates was designed to deny Trump from winning the nomination on the convention's first ballot and assist rival Ted Cruz.

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