Wimbledon fourth seed David Nalbandian could miss next week's grasscourt grand slam with a rib injury.
The Argentine, a runner-up at the All England Club in 2002, was forced to retire after just five games of an exhibition match against Chilean Nicolas Massu at the Boodle and Dunthorne Champions Challenge at Stoke Park yesterday.
Nalbandian is yet to make a statement on his condition but there are fears in his camp he could be forced to withdraw from Wimbledon.
A semi-finalist at the U.S. Open last year, Nalbandian has been seeded to meet Britain's Tim Henman in the quarter-finals.
The injury is a major blow to a player who uses strength and fitness to grind down opponents from the baseline.
While not considered a traditional grasscourt player, the burly Nalbandian enjoyed a magical run at the tournament in 2002, reaching the final in his first grasscourt event before losing to Lleyton Hewitt.
One glimmer of hope for the Argentine is that, being in the bottom half of the draw, he will not be expected to play his first round match until Tuesday.
Nalbandian has a tough first round draw against acrobatic Croatian Mario Ancic.
If he is forced to withdraw, his place will be taken by a lucky loser from the qualifying draw.
Wimbledon, the only one of the four grand slams to be played on grass, takes place from June 21st to July 4th.