"It's literally just bowling, it's not running, I can do boxing, weight sessions, rowing, anything like that but as soon as the pressure at the crease of match intensity when I step it up, literally I just burst blood vessels in my lungs," Hastings told the Herald Sun.
"I walk back to my mark and cough up some blood so it's pretty scary but they can't tell me for sure that it's not going to cause long-term damage so there's a lot of grey area surrounding it.
"The important thing is I've been cleared of anything massively sinister so I'm healthy.
"I'm OK, it's just I can't bowl for the foreseeable future so I'm trying to find answers but unfortunately at the moment it's not looking good.
"To see it maybe slipping away, it's pretty tough to take and at this stage unless something miraculous happens I won't be able to bowl."