The Sharks co-captain makes his comeback against North Queensland on Friday, after his future was thrown into doubt by the second ACL injury of his career last August.
Few play the game tougher than McInnes, who wears false teeth following on-field dental injuries and was the first man in recorded NRL history to make 80 tackles in a game.
But Cronulla coach Craig Fitzgibbon never feared the 32-year-old's body would give up on him amid the ACL recovery and force him into premature retirement.
"He's too tough to let that happen," Fitzgibbon told AAP.
"A player like Cam, generally he'll choose. Mentally, for players like that, they know, no one else knows because they'll never show you what they're actually going through.
"We never had any doubt or cause for concern, and he had no hiccups in his recovery."
ACL injuries can often take the best part of a year to heal well enough for an NRL player to return to the field.
Warriors co-captain Mitch Barnett needed a little less than 10 months to bounce back from the one he suffered last June.
Dolphins winger Jack Bostock is still not back on the field after going down in late June, almost two months before McInnes suffered his own injury.
McInnes' recovery in a little more than eight months is already much quicker than average, but the man himself was convinced he was fine to play even earlier than round eight.
"He's been hard to hold back, that's for sure, he's definitely been pressuring the performance staff," Fitzgibbon said.
"Cam's been ready to play for a while now, but sometimes we've got to protect Cam from himself."
The Sharks have long been eager to give off-contract McInnes the chance to play a solid stint of games before turning to the contract table for 2027.
Already a popular figure at the club, he has impressed the even further in his time away from the field.
"He's a meticulous professional, I don't think he could've done any more in his time off to have himself mentally and physically ready," Fitzgibbon said.
