Hazlewood played just three matches in the IPL for Royal Challengers Bangalore after arriving to the tournament late due to an Achilles issue that saw him miss Australia's entire four-match Test series with India in February and March and the three-match ODI series that followed.
The decision to withdraw Hazlewood from the IPL early was precautionary and scans cleared him of any damage to his side. He has suffered two side strains in the past two years which saw him miss four Tests in the 2021-22 home Ashes series and then three more last summer against West Indies and South Africa.
But he was able to bowl at home in Sydney before travelling with the team to England last week. The squad held their first official training session in England on Tuesday in Formby in West Lancashire where Hazlewood went at close to full tilt having had a gentle bowl on his own shortly after arriving in England.
He told the ICC that he is close to full fitness but would need to get through a week's worth of bowling to be declared fit to play in the WTC final against India starting next Wednesday at the Oval in London.
"My fitness is pretty good," Hazlewood said. "It is just a matter of ticking off every session from here until that date basically.
"In T20 you are bowling a lot of various different balls every over. A wide yorker to a bouncer to a slower ball, and [the side] just got jammed up a little bit and a bit of scar tissue from previous injuries flared up.
"It calmed down pretty quickly. I had a week off, I didn't quite get back to going 100 percent at [the] IPL, but the last few bowls have been good and I have been building up nicely."
Australia began their UK tour in Lancashire with a golf trip that included a training session at Formby on Tuesday before heading to London on Wednesday where they will hold a three-day camp at Beckenham.
Hazlewood will likely have to get through two solid bowling sessions on Thursday and Saturday if he's any chance to play in the WTC final. Australia will train at the Oval on Monday and Tuesday and the quicks often have another solid bowling session two days out from a Test match before resting the day prior to the match.
Australia's side will be settled for the WTC final outside of the decision between Hazlewood and Boland, with Pat Cummins returning to captain the team after missing the last two Tests in India for family reasons. Mitchell Starc is fully fit having played as the lone quick in Australia's final two Tests in India after missing the first two due to a finger injury.
Hazlewood has only played four of Australia's last 19 Test matches and has not played in back-to-back first-class games since early 2021. He was aware that six Tests in seven weeks would be a big ask for the fast bowlers to undertake despite a desire to play every game.
"If you asked that question three years ago I probably would have said I would have liked to play all six Tests, but it is just different now," Hazlewood said. "It is just so tightly consumed together now and coming off not an ideal build-up, it is getting there now.
"But we have got enough quicks here and a couple of others playing county cricket to cover all bases. Pat is perhaps looking at all six potentially depending how much we bowl in each so you play it by ear a little bit. It is such a dense schedule, it is tough."
Alex Malcolm is an Associate Editor at ESPNcricinfo