The Argentine former U.S. Open champion slipped during his victory over Denis Shapovalov on Wednesday and later pulled out of the grasscourt tournament.
His hopes of playing at Wimbledon were dashed on Thursday after scans revealed he had fractured his right patella -- the same injury that forced him to miss the last four weeks of 2018 and restricted him to five tournaments this year.
The ATP's website said the 30-year-old world number 12 had consulted with his doctor Angel Cotorro and that surgery was required within the next couple of days.
Since winning the 2009 U.S. Open, Del Potro has been robbed of large chunks of his career, undergoing three left wrist surgeries and another to his right wrist.
He had shown signs of returning to his best form and had risen to fourth in the rankings in January.
(Reporting by Martyn Herman; Editing by Toby Davis)
