Whether it happened beneath the beating sun of December training or ahead of his selection to play Port Adelaide and Essendon in the NAB Challenge series, only he knows.
Those who watched Warren represent VFL side Werribee last year would have seen his potential, but also the gap he needed to bridge to be considered for senior selection.
Warren was aware of it too, yet the weight of possibility convinced North Melbourne coach Dean Laidley the cotton-topped forward deserved a third year on the list.
"Not to say they were disappointing, but the last couple of years have been massive development years," Warren said.
"Over the pre-season I started to realise I'm here to play footy. That's what I hunger for and that's what I want to do.
"It's about time. The Roos drafted me for a reason, not to sit on the list but to make an impact.
"I know that and hopefully with what I've done through the pre-season, I take my opportunity. I've got to make it happen."
Warren, 20, is now preparing for his AFL debut after being named at half-forward in North's side to play the Bombers on Sunday.
Recruited as a 17-year-old from the Zillmere Eagles with pick No.69 in the 2006 NAB AFL Draft, Warren arrived at Arden Street fresh-faced and with his family still in Queensland.
He played one NAB Challenge match against St Kilda in early 2007 before spending the year with Tasmania in the VFL, North's second affiliate at the time.
But greater development came in 2008, even after a bout of osteitis pubis hampered him early on.
"I loved playing there," Warren said of his time with Werribee. "The coach (Simon Atkins) was great and I had a pretty solid year."
Midfield roles now await Warren at that level – a sign of the gains he has made in his game.
"I've come a long way," he said. "I was always not too bad athletically but I've definitely improved a lot in every area. I'm a more rounded player."
Until recently, Warren lived with teammates Leigh Adams and Ben Ross but has moved in with his parents, who re-located to Melbourne last year to enhance his younger brother's football prospects.
Warren, who grew up idolising Collingwood's Nathan Buckley and Brisbane Lions premiership hero Michael Voss, is enjoying the stability of the home life he had before he was drafted.
"It was [challenging] for the first year, missing home and stuff like that," Warren said. "It wasn't too bad but now I get to see my parents a lot more.
"I've definitely had to grow a lot as a man because I came here as a boy."
And his emergence hasn't been lost on assistant coach Darren Bewick, who has worked closely with Warren in North's forward group.
"He's matured a lot on and off the ground," Bewick said last month. "He's a very hard worker and his ability to hit up and lead is a real strength.
"He might get [senior] opportunities, which is a great credit to him."
North Melbourne
B: Scott McMahon, Scott Thompson, Daniel Pratt
HB: Gavin Urquhart, Lachlan Hansen, Josh Gibson
C: Brady Rawlings, Michael Firrito, Leigh Harding
HF: Brent Harvey, Drew Petrie, Ben Warren
F: Matt Campbell, David Hale, Lindsay Thomas
Foll: Hamish McIntosh, Adam Simpson, Jack Ziebell
I/C: Ed Lower, Josh Smith, Sam Power, Andrew Swallow
Emg: Levi Greenwood, Daniel Harris, Todd Goldstein
In: Warren, Lower
Out: Daniel Wells (hip), Corey Jones
New: Ben Warren (Zillmere Eagles)
Essendon
B: Dustin Fletcher, Darcy Daniher, Henry Slattery
HB: Tayte Pears, Adam McPhee, Courtenay Dempsey
C: Angus Monfries, Brent Stanton, Ricky Dyson
HF: Jason Winderlich, Scott Lucas, David Zaharakis
F: Patrick Ryder, Matthew Lloyd, Alwyn Davey
Foll: David Hille, Jobe Watson, Andrew Lovett
I/C: Hayden Skipworth, Mark McVeigh, Michael Quinn, Jay Nash
Emg: Leroy Jetta, Sam Lonergan, Nathan Lovett-Murray
In: McVeigh, McPhee, Quinn
Out: David Myers, Heath Hocking (toe), Leroy Jetta
