Juan Martin Del Potro only played five tournaments in 2019 before having to undergo another knee surgery in June. In his most recent match, he defeated Denis Shapovalov before withdrawing in the second round of Queen's Club after re-fracturing his right knee.
The injury forced the 30-year-old to miss Wimbledon and US Open. Del Potro finished runner-up to Novak Djokovic in the 2018 US Open. It's been 10 years since he captured his own US Open title, beating Roger Federer in the 2009 final.