Former England batsman Gary Ballance is suffering with "anxiety and stress", his county, Yorkshire, said Saturday.
The 30-year-old left-hander, who played 23 Tests and 16 one-day internationals from 2013-2017, has not appeared for Yorkshire in a season delayed by the COVID-19 outbreak.
"Gary is currently managing some heightened feelings of anxiety and stress following a long period of isolation due to the COVID-19 lockdown, his own recent viral illness and other personal factors," said a Yorkshire statement.
"The post-viral symptoms have affected his physical preparation for this shortened cricket season. He is currently unavailable for selection and we are unable to put any timescales on his return to playing at this time.
"Gary's health and well-being remains our priority and the club and medical staff will continue to work closely with Gary to support his return to playing as soon as possible."