Leander Paes, one of the world's best doubles tennis players, is being treated for a brain lesion and will miss the upcoming US Open.
Paes, 30, suffered severe headaches late last week. He checked himself into an emergency room near his Orlando home on Sunday, and a scan showed a lesion in the left occipital region of the brain.
He was transferred to MD Anderson Cancer Center in Orlando on Tuesday, hospital spokeswoman Michelle Lynch said.
Tests are being conducted to determine the lesion's cause, with the results expected within a few days. A brain tumor has not been ruled out, Lynch said.
He is alert and speaking, Lynch added.
Paes teamed with Martina Navratilova last month to win the mixed doubles title at Wimbledon, earning her a record–tying 20th championship at the All England Club. Paes and Navratilova also won the mixed doubles title at the Australian Open in January.
Paes has won 27 men's doubles tournaments, including the 1999 and 2001 French Opens and the 1999 Wimbledon title. He was ranked as the ATP's top doubles player in 1999.