VERSAILLES, France (AP) England's Lee Westwood has been taken to hospital for tests after a doctor feared a swollen calf muscle could be caused by a blood clot.
Westwood had been expected to play in Wednesday's pro-am before the start Thursday of the Alstom Open De France in Versailles.
But the 37-year-old player withdrew, saying he was going to "have it checked out."
If serious, it could affect Westwood's availability for the British Open at St. Andrews, which starts July 15.
The pro-am had three other withdrawals on Wednesday. Ian Poulter with an insect bite; Colin Montgomerie with a calf injury; and Matteo Manassero with an injured wrist. All three are expected to play in the tournament.
The 17-year-old Manassero was hit in the hand by a golf ball while practicing on the 11th hole Tuesday at Le Golf National.
"We called the group behind us through and one of the drives hit me - the ball didn't bounce first it was full on ," he said. "I did not want to risk making the injury worse before the tournament. It is a very important one for me with big prize money."
Since he turned professional at the start of May, Manassero is allowed only a maximum of seven invites in which to earn enough money for his tour playing card for next year.
He has already used up four, making the cut each time and winning more than $61,000. But it is estimated he will need to win around $300,000 to avoid having to go to tour school in the fall.