John Hastings will take an indefinite break from cricket and is unsure whether he will return due to a mystery lung condition.
The all-rounder, who has played for Australia in all three formats, has been suffering from bleeding on his lungs when he bowls.
Hastings, 32, has been advised not to continue bowling as doctors cannot rule out more serious complications.
"Thank you to everyone for your well wishes and support it really means a lot." Hastings, who was due to play for the Sydney Sixers in the 2018-19 Big Bash League, tweeted.
"The important thing to note is that other than when I am bowling I am in good health, it is just a situation that is extremely rare and is unfortunately affecting my cricket.
"It's a tough thing to come to terms with but there are a lot worse off people than me. I am very fortunate to have my management team Gerard Sholly and Tony Box, who have been unbelievable.
"Also Jodie Hawkins from the Sixers, who have been amazing, as has my family and friends and our wider cricketing family. I am in good hands.
"Been a tough period but getting through it."