Lokomotiv Moscow youngster Innokenty Samokhvalov has died while engaging in a solo training session during Russia's coronavirus lockdown.
The 22-year-old's tragic death was announced by the Russian Premier League club via statement and their social media accounts on Sunday.
Samokhvalov had been training at his property to keep fit with Russia's government imposing restrictions around football clubs' training sessions due to the Covid-19 pandemic.
"On April 20, defender Innokenty Samokhvalov died, " the statement from Lokomotiv said. "The footballer became ill during an individual training session. Details of the tragedy are being clarified.
"Samokhvalov left a wife and a son. FC Lokomotiv is shocked by what happened. This is a huge sorrow for our family."
The club also tweeted: "Kesha was a kind, helpful person and a good friend. We are truly shocked by what happened and express our sincere condolences to his family and friends."
Samokhvalov was yet to make a senior appearance for Lokomotiv since joining the club in 2015 and had been playing for their reserve team Kazanka in the third tier of Russian football.
While speaking with Russian media, Kazanka's coach Alexander Grishin suggested Samokhvalov's cause of death was a heart issue.
"It's horrible. The doctors have told us the cause of death was heart failure," Grishin told Russian news agency RIA Novos.
"If the doctors allowed him to train then we must assume he did not have any problems."
Moscow residents were forced into a lockdown by Russian president Vladimir Putin in late March as the coronavirus began to become more prevalent in the country.
Shortly after, the Russian government announced a non-working period for citizens that has since been extended until April 30.
Russia has suffered 405 deaths from Covid-19 from 47,121 cases - while 3,446 people have recovered from the illness.
Coronavirus has had a significant impact on the football globally, with most leagues worldwide forced to suspend their competitions and prohibit team training.
Several star footballers have contracted the illness, including Juventus trio Paulo Dybala, Blaise Matuidi and Daniele Rugani, while other high-profile sufferers include Arsenal coach Mikel Artera and Olympiakos president Evangelos Marinakis.