Kei Nishikori's first Grand Slam appearance in almost three years was curtailed by a shoulder injury that forced him to retire in the second round of the French Open on Thursday.
The former world No. 4 threw in the towel after dropping the first two sets to American No. 15 seed Ben Shelton before rain again interrupted a match that began on Wednesday.
"I have been struggling with my shoulder for two, three months now, and it got better," said Nishikori, whose ranking has plummeted to No. 350 after a lengthy injury absence. "I thought I was ready to play before first round, so I played."
Nishikori won his opening match at Roland Garros, defeating Canadian qualifier Gabriel Diallo in a five-set marathon lasting 4 hours and 22 minutes on Sunday.
But those exertions took their toll, and brought a sad ending to Nishikori's first Grand Slam appearance since the 2021 U.S. Open.
"Unfortunately played five sets and my shoulder was not ready," he said.
"Beginning was okay, but start hurting after playing first set and second set, and maybe I could play one more set, but it start, like, buzzing and start feeling something, sharp pain, so I stopped."
The 34-year-old Nishikori, the 2014 U.S. Open runner-up, has barely played on the tour in the past two years following a succession of injuries to his hip, ankle and knee.
He used a protected ranking to compete in Paris.