"Mr. Trump," began a note that was scrawled on a baseball and posted to Trump's Twitter account. "Please make America great again" — an apparently reference to Trump's infamous slogan.
The ball seemed to be signed by Rose — but on Monday lawyer Ray Genco disputed that his client had offered any endorsement.
"Pete has made a point not to 'endorse' any particular presidential candidate," Genco said in a statement to NBC News. "Though he respects everyone who works hard for our country — any outlet that misinterpreted a signed baseball for an endorsement was wrong. Pete did not send any candidate a baseball or a note of endorsement."
Genco added that through his "discussions with Pete about this cycle, I've learned that he believes that who to vote for is a decision each voter should decide for him or herself."
Earlier Sunday, Trump announced that Rose should be allowed in Major League Baseball's Hall of Fame.