London, June 20: The unfortunate Juan Martin del Potro has suffered another injury setback less than a fortnight before Wimbledon.
Del Potro hurt his knee when slipping during a first-round victory over Denis Shapovalov at the Queen's Club Championships on Wednesday.
The 2009 US Open champion only returned to the ATP Tour at the Madrid Open in May after an absence of almost three months, during which time he underwent new regenerative knee treatment.
Del Potro could face another lay-off after the injury-plagued Argentine's fall on a rain-affected day of his first grass-court tournament of the season in London.
Jorge Viale, the former world number three's spokesman, tweeted: "Juan Martin del Potro finished his first-round match at Queen's with pain and swelling in his right knee after slipping close to the net in the eighth game of the second set.
"In the next few hours, medical studies will be carried out to determine the degree of the injury. We will report the results in a timely manner."