The 24-year-old had previously looked well set in the Red Rose No.2 shirt after a run of seven consecutive starts before picking up an injury in the Saints' Premiership play-off semi-final defeat to Saracens.
Contrary to reports coming out of the England camp, Hartley maintains he will be fully fit for the season opener against bitter rivals Leicester and is determined to lay down the gauntlet to his former Northampton mentor.
He said: "When you're playing in any shirt for England, it's yours to lose and I had it for eight or nine games and had a good run at it.
"Then I had to take the decision to get my knee op, which meant handing over my shirt to someone else.
"Steve's taken that and it'll be hard for Johnno to look at the team and change it after going to Australia and winning so well.
"It's up to me to fight back and work hard to try and get that shirt off his back. Leeds last year were a forward-dominant side and he'll add to that.
"I'm raring to go after watching England beating Australia and watching the boys playing well.
"I've got a hard road ahead of me to even get in the Saints team at the moment - all the other hookers are looking fit and strong and they're about three or four weeks ahead of me.
"We've targeted a couple of weeks before the first league game so hopefully I'll make the away trip to Dax in France or Viadana at home. Hopefully I'll be in contention to play Leicester.
"There's two sides of looking at it. There was the side where I had to sort my knee out sooner rather than later.
"If I'd have left it, it would have broken down at some stage. It was quite mature of me to sit back and say: 'fix my knee'.
"Then again, to miss that tour was gutting. I'd been involved in every game under Johnno up until that tour.
"For the lads to go down there and win and win well was fantastic and it looked like the trip of a lifetime. Tours are always good fun and I was a gutted to miss out on that."