By Tony Jimenez TROON, Scotland (Reuters) - Former Ryder Cup player Francesco Molinari has joined a growing list of golfing withdrawals from next month's Olympics in Rio de Janeiro. The world's top four -- Jason Day, Dustin Johnson, Jordan Spieth and Rory McIlroy -- have pulled out due to health worries, three of the quartet citing concerns about the Zika virus in the Americas. "I have decided to withdraw from the Italian Olympic team due to family reasons," Molinari said on Instagram without elaborating. ... More...