Lynn, one of the most potent sloggers in short-form cricket, has a history of serious shoulder injuries and dislocated his right one diving to field a ball in a Twenty20 international against New Zealand in February.
"It's something not worth risking," Lynn told reporters in Perth on Wednesday.
"If the ball is touch and go, then I'm better off just letting it go for four or whatever it may be than potentially missing four to six months with a shoulder injury.
"I've been in that situation too many times now. Mentally it's tiring. Obviously, physically it is, but mentally it's probably twice as hard.
"I don't know how many times the shoulder can take it."
The 28-year-old has been recalled in a new-look Australia one-day international squad captained by Aaron Finch, with former skipper Tim Paine jettisoned after leading the team to a 5-0 series defeat in England.
He has opted out of playing in the domestic Sheffield Shield competition, so will need to impress selectors with a pile of runs in three ODIs against South Africa starting in Perth on Sunday.
Even then, the chances of breaking into Paine's test side were slim, Lynn conceded.
"I don't want to get too far ahead of myself, but if I do happen to score runs in these next three games, then obviously I'd put my hand up for test selection, but I think that's a little bit out of the equation," he said.
Australia's T20 side were hammered 3-0 in the recent series against Pakistan in the United Arab Emirates, and Lynn said the country's batsmen needed to be more calculating than aggressive at the crease.
"We saw over in the UAE we probably took too many risks," Lynn said.
"We want to play fearless cricket, not reckless, and I think there's a massive difference there. So maybe put our egos aside a little bit and just bat. Spending time in the middle is the best way to do that."
(Reporting by Ian Ransom; Editing by John O'Brien)
