Hartlett, 19, has been hampered by injury and illness since arriving at Alberton via pick No.4 in the 2008 NAB AFL Draft.
The club's highest-ever draft selection missed 11 games through injury last season, including two stints on the sidelines with unrelated hamstring complaints.
He was struck down with glandular fever before Christmas and had only been in full training a few weeks when he injured his hamstring again, this time suffering a grade-one tear.
Hartlett's latest setback was the final straw for coach Mark Williams, who placed his prized midfielder on a modified training program similar to the one used by battle-hardened veterans Warren Tredrea, Chad Cornes and Dean Brogan.
Hartlett's program also includes acupuncture sessions twice a week.
"Choco [Williams] lay down the law after this most recent injury. He said I would only be training every second day and would never do two sessions in one day. I certainly won't be training hard one day and hard again the next. I'll be having one day off in between," Hartlett said on Wednesday.
"Obviously I'm not capable of putting up with the workload of a full AFL pre-season yet. It's something the club will work with me over the next year or two to overcome. I've got to do other things to keep my body in check and keep on top of it all."
Port Adelaide has demonstrated its faith in the impressive teenager by handing him former vice-captain Shaun Burgoyne's No.8 guernsey this season.
Skilful half-back Nathan Krakouer has also moved lockers, swapping No.29 for his retired idol Peter Burgoyne's old No.7.
Defender Matthew Broadbent, who wore No.32 last year, will take over the No.5 formerly worn by dual All-Australian ruckman Brendon Lade.
Krakouer and Broadbent were given the prestigious jumper numbers at the request of Burgoyne and Lade respectively.
But Hartlett said his decision to switch from the No.22 was a matter of preference.
"I've always loved single-digit numbers, so anything from one even through to number 10 would've been fantastic," he said.
"To have No.8 after Shaun, a premiership player with the club, is a fantastic honour. Hopefully, I'll be the next premiership player at Port Adelaide to wear the No.8."
Draftee Jasper McMillan-Pittard has also opted for a change this year.
The chatty teenager will no longer require a hyphen in his name, after dropping the 'McMillan' from his surname for simplicity's sake.
Like Pittard, Hartlett will be looking to stake his claim on a place in the side during the NAB Cup competition, which kicks off against Adelaide on February 13.
Hartlett has been ruled out of the first two games, but said he was confident of returning to the field before round one.
"It's vital to get a good pre-season under your belt and I've missed a little bit, which has been disappointing, but I've got full faith in the medical staff to get me back to where I need to be by the start of the season," he said.
"They've all been different injuries, so until I get a consistent injury that's recurring I'm not overly worried. I'll just listen to the advice I get from the fitness staff and the physios and do what's required of me to get out on the park for as long as I can."
