The Irishman injured a thigh in the warm-up just minutes before Hibs’ final pre-split fixture with Aberdeen.
The injury was supposed to rule him out of the final month of the season but he managed to declare himself fit for their final-day clash with Kilmarnock.
The Leith side lost that crucial clash, though, as they dropped into the play-offs but former Killie striker Heffernan is now looking forward to Sunday’s second leg against Hamilton determined to make up for lost time.
Hibs lead 2-0 following Wednesday night’s clash at New Douglas Park and the 32-year-old said: “I picked up the injury not that long ago in the warm-up at the Aberdeen game. It wasn’t ideal and I thought I would have been out for the season.
“As it’s turned out, the play-offs have extended the season. I’ve managed to get myself fit again and at the minute I feel good - it’s just a shame the season is coming to an end now.
“But in a way, it’s been good for me that we’ve had the play-offs because at least I’ve managed to get back playing and can now try to do my part and help the team out.”
Teenage hitman Jason Cummings struck his first pair of goals for Terry Butcher’s side to put them ahead of Accies.
But Heffernan insists Hibs still have work to do to preserve their top-flight status.
“You’ve got to try to treat it as if it’s still 0-0,” he said. “It’s another game that you are starting off from scratch and want to win so, that’s the way we are going to approach the game. We don’t want to go into the last 15-20 minutes a bit nervy and all of a sudden they get a deflected goal. We’re going to attack and hopefully get an early goal.
“There is a confidence within the group that we can go out and beat anybody on the day but talk is cheap. We had a good two weeks training and we were fully prepared and focused for the Hamilton game and I think the performance showed that the break done us good. We looked good, strong and disciplined and that’s what we need again on Sunday.”