He had detoured to North's Arden Street training headquarters on his drive home from Geelong's Simonds Stadium, figuring that with his wife, Nicole, and young children Jack and Abby away for the night he might as well sneak in some extra recovery work.
It was barely two hours since the final siren had sounded on North's round three NAB Cup loss to Geelong, a game that had been played in stifling conditions that hovered around 36 degrees all day.
Despite both teams being allowed extended benches of six interchange players and unlimited rotations, Petrie did not leave the ground once during the game.
When the key forward weighed himself straight after the match, he had lost 3.5kg, nearly double the 2kg he normally loses during a game.
Petrie had also suffered a minor corked left calf muscle during the game, having received an accidental kick in a contest.
Behind the scenes special: Inside Petrie's week
The modern footballer is programmed so recovery is his post-match default mode, but Petrie has long been renowned for going over and beyond club-stipulated sessions.
Now that he's 30, Petrie is even more mindful of squeezing in extra bike rides or pool sessions when he's feeling sore.
Which explains his visit to Aegis Park last Saturday night.
The North co-vice-captain had already completed team recovery at Simonds Stadium, but wanted to do more to prepare himself for North's next game, against Hawthorn at Craigieburn this Saturday.
AFL.com.au has shared that recovery journey with Petrie over the past week, gaining valuable insights into just what a player has to do to get himself up from one match to the next, and the mental and physical challenges he faces in that race against time.
Preparing for battle: North Melbourne players in a final team talk before taking on the Cats
SATURDAY
Post-game, Simonds Stadium changerooms:
(1) Eats some fruit and drinks a protein shake
(2) Ices his left calf muscle for 10-15 minutes
(3) Ice bath
(4) Wraps left calf in a compression bandage to further reduce its swelling
(5) Eats a chicken wrap and drinks a diet coke and sports drink to replenish his sugar levels
When Petrie started his AFL career in 2001, post-game recovery largely meant static stretching.
But the quadriceps, hamstring, groin and calf stretches that were recovery staples for generations were nowhere to seen in North's changerooms last Saturday.
Petrie explains the prevailing view now is that static stretches offer no real recovery benefit, with active stretches – stretching with movement; leg swings, windmills and such – and ice baths far more effective in reducing muscle swelling.
"The ice bath is not a pleasant experience. It's probably one part of footy that you just don't get used to," Petrie says.
"But there's a lot of swelling in your legs post game.
"You just want to get that down, get your core body temperature down, so you can start to heal and recover.
"As soon as I hopped out today my legs felt a whole lot better."
Petrie says the post-game licence players are given to satisfy any junk food and soft drink cravings is a welcome relief from a diet that otherwise is heavy on fruit, vegetables, water and, in the two days before a game, carbohydrates.
"After a game of footy I don't feel like eating a salad or anything like that, I feel like a pizza or a hamburger," he says.
"It's the only time of the week we know we can have this stuff and get away with it, so I like to enjoy it.
SATURDAY NIGHT
At Aegis Park:
(1) Bike ride
(2) Ice bath
At home:
(1) Ices his calf muscle every 90 minutes for 10-15 minutes before he goes to bed
SUNDAY
Recovery session at Aegis Park:
(1) Bike ride
(2) Two laps running, stretches, strides at 60-70 per cent effort
(3) Strength exercises
(4) Ice bath
Petrie also kept his left calf in a compression bandage all day and iced it regularly.
"I didn't feel too bad," Petrie says after the session. "My calf felt pretty good. It's just a small corkie.
"Back when I started recovery was just a 10-minute dip in Port Phillip Bay, but now it's a bit more structured and takes 11Z2-2 hours."
MONDAY
(1) Strengthening exercises
(2) Match review at 9am, which involves all 45 of North's listed players and its coaching, medical and fitness staff viewing edited video from the Geelong game
(3) Skills session at 10am
a. Half-ground ball movement, including kicking and leading
b. Touch work
c. Goalkicking: including snaps, torpodeos, and set-shot drop punts
(4) Weights
Inside the club: Early morning at Aegis Park, Petrie gets prepared for a training run
"I felt like crap," Petrie says afterwards. "It's usually the second day after a game that I'm sorest."
Unlike some clubs, North's medical and conditioning staff does not put limits on the amount of goalkicking practice their players can do. Petrie says he has a total of about 50 shots at goal each week in North's set goalkicking sessions.
He says he did more goalkicking at the start of his career, especially at the end of training, but that was before the huge spike in core strengthening and recovery work players now do.
"I would like to take more shots at times, but I know after training I've normally got to do core (strengthening), weights and an ice bath – it's a juggling act," he says.
"We were a bit sceptical about the core stuff for the first 12-18 months after we started doing it because you can't see tangible gains like you can with weights. But when the team's soft-tissue injuries start to drop to almost nothing, you can see the benefit."
TUESDAY
(1) Strength exercises
(2) Bike ride
(3) Massage
(4) Half-ground training drills
(5) Ice bath
(6) Physio
A day can make all the difference in the recovery process.
"I feel really good," Petrie says after the preparation day when North players are given the freedom to decide what they need to do to get their bodies right for the following day's main training session.
"I feel a lot better and no doubt by tomorrow when I hit the track I'll be even better.
"It does take the better part of three days to get over a game."
WEDNESDAY
Main weekly training session:
(1) Strength exercises
(2) Weights
(3) Opposition preview - focusing on Hawthorn
(4) On-ground session
(i) Warm-up
(ii) Skills
(5) Weights
(6) Physio
(7) Massage, focusing on Petrie's back and glutes - "the two areas that stiffen up the most for me"
(8) Ice bath
"I feel as though I've recovered entirely from the game against Geelong," Petrie says afterwards.
"It was a really long main session, probably our longest in the past month.
"Five years ago we used to do two main sessions a week. But these days it's one really big session and a couple of smaller technical sessions.
"It's about recovering from the game and enabling yourselves to have a really good session in the middle of the week so you're not dropping off too much fitness.
"I think it's really important that you have a big hitout once a week where you train at almost maximum effort, and keep your body used to running at speed, changing direction, jumping, bending over and allthose movements you need in a game."
Back on the track: Petrie does a handball drill during North Melbourne's main session
THURSDAY
Day off
Petrie says before he became a dad he would go into the club on his day off and have a bike ride, massage and ice bath. But today he took his daughter Abby, who is nearly one, swimming, then took care of some chores he doesn't normally get the time to do.
"The mental break is good for me. Some of the stuff we do at the club is quite repetitive, which can make you stale," Petrie says.
"But after a day off I go back into the club the next day excited about what I have to do."
Dinner
A generous bowl of fettuccini amatriciana, garlic bread and water.
This meal marks the start of Petrie's carbohydrate loading for the game. He also has a bowl of pasta for lunch on the day before a game, Friday this week.
Later in the week he also tends to start to snack on fruit and muesli bars, bypassing the muffins, banana bread or lollies he might indulge in before that. "You've got to let yourself know you're alive every once in a while," Petrie jokes about his sweet tooth.
Other than that his diet stays fairly standard during the week: cereal (four Weet-Bix and a sprinkle of Sultana Bran) and perhaps some toast for breakfast, a salad sandwich for lunch and meat or fish and vegetables or salad for dinner. He does not normally add salt to his food, but makes an exception on the night before a game, sprinkling some on his vegetables to guard against cramping the following day.
FRIDAY
(1) Strength exercises
(2) Light skills session
(3) Physio
(4) Ice bath
Night:
Petrie likes to be in bed by 10pm on the night before a game and generally nods off soon after his head hits the pillow.
After dinner, he does not like to sit still, preferring to keep himself busy with household chores like the dishes.
"There's always something that needs doing and I don't like to sit still because I know I'll start thinking about the game," Petrie says.
SATURDAY
Pre-game routine:
Petrie has his standard cereal and toast for breakfast, a banana and honey sandwich before he leaves for the game and perhaps a piece of fruit just before game-time.
Again, he likes to keep himself busy before he leaves for the ground and, if his children aren't asleep, is happy to do the vacuuming.
On the eve of the game against the Hawks at Craigieburn this Saturday, Petrie says his week of recovery work and training has left his body feeling fantastic.
"I feel a million bucks. With a bit of help from the physios, I've worked out all the little kinks from the Geelong game, so I should be ready to go against the Hawks."
Surprisingly, Petrie thinks, at 30, he is recovering from games as well as he ever has.
And he says that is only partly because he's now sneaking in more and more extra recovery sessions.
"My body now knows how to fix itself in three or four days after a game," Petrie says.
"There are all the recovery things you have to do to it to fast-track that, but I think my body is more resilient than it used to be."
Practice makes perfect: Drew Petrie's attention to detail shone through as AFL.com.au was granted inside access to follow his recovery and preparation throughout the week
