TOKYO -- Former world No. 4-ranked and 2014 US Open finalist Kei Nishikori said Thursday on social media that he plans to retire at the end of this tennis season.
Nishikori, 36, missed the Australian Open in January because of right shoulder pain and has been affected by injuries the past several years. He also missed last year's US Open.
After making his professional debut in 2007, Nishikori became the first Japanese player to advance to the final of a Grand Slam men's singles tournament at the 2014 US Open, which he lost in straight sets to Croatia's Marin Cilic.
Nishikori, who won a bronze medal at the 2016 Rio Olympics after defeating Rafael Nadal in three sets, said in early April that he was "barely hanging on," referring to his physical condition.
"Looking back on everything up to this point, I can proudly say I gave it my all," Nishikori said on X. "I am truly happy to have walked this path."