Republicans are increasingly worried that a Donald Trump presidential candidacy could drag down their strongest field in recent memory.

“He’s an unwelcome distraction,” said Republican strategist Ron Bonjean. “We already have so many candidates vying for attention, and he brings a sideshow element to the whole thing.”

Trump, a billionaire real estate mogul and reality TV star, has scheduled a “major” announcement from Trump Tower in New York City on June 16. Speculation is rampant that he will enter the White House race, one day after former Florida Gov. Jeb Bush (R) is virtually certain to make his own candidacy official.

Some Republicans remain skeptical that Trump will actually join the field, however. He has flirted with running in every cycle since 2000, most notably in 2012, when he was briefly at the top of the GOP polls. But he’s never taken the plunge.

Note: Fixed headline at 11:07 am ET. — Ed