The 29-year-old announced last month that he was hanging up his boots after failing to overcome neck and knee injuries.
Flanker Warburton, who led the Lions on successful tours to Australia in 2013 and New Zealand last summer, had not played since the drawn third All Blacks Test 12 months ago and could not regain his fitness during pre-season training with Cardiff Blues.
“I remember saying to the physio, ‘I’m fine but when I tackle or run, that’s when I get pain,'” Warburton told the Times. “He was like, ‘That is a bit of a problem doing what you do.’ ”
“When I was doing overhead press in the gym, I was still getting nervy symptoms, pain in my neck, and I hadn’t even done any contact work. After a week I was coming home from training and I was having joint pain – you can deal with muscle soreness but this was different.
“I didn’t want to be that player who was just hanging on, holding a pad. If I couldn’t get to the heights I wanted to, I’d rather just call it a day.
“If I couldn’t get to an international standard, I was not going to do it and I could tell I wasn’t going to make that after about a week’s training. My body just couldn’t cope with the volume of running anymore.”
Warburton admits that next year’s World Cup in Japan made his decision to quit more difficult.
“We finished our session and we were in a huddle. Some of the senior players and coaches were talking and I remember not being as focused as I should have been, looking at the grass,” he added.
“I was just thinking, ‘This is it. I have found that session so hard, what with all the changing of direction. My knees are so sore’. I just thought, ‘I am never going to get through 14 months to get to the World Cup’.”
The Wallabies face another daunting task when they take on the All Blacks at Eden Park on Saturday morning (11:35 UAE time).
After last week’s comprehensive win in the Rugby Championship opener in Sydney, Steve Hansen’s side are on the brink of sealing their 16th successive Bledisloe Cup against their trans-Tasman rivals.
Here, we take a look at the main talking points going into the fixture.
Black magic at Eden Park
The All Blacks are on a 41-match unbeaten run at the Auckland venue since being beaten there by France in 1994.
In fact, their opponents for this weekend, Australia, haven’t won anywhere in New Zealand since Dunedin in 2001 and last tasted victory at Eden Park 32 years ago with a 22-9 result in 1986.
Since then they have lost 17 Tests to New Zealand in Auckland.
At Eden Park, the All Blacks are even more dominant over the Wallabies with an 85 per cent success rate, having won 23 of 27 Tests.
It doesn’t look like it will get any better either for Michael Chieka’s side, who look low on confidence.
Franks 100 not out
Last week it was Sam Whitelock celebrating his 100th cap, now it’s Owen Franks’ turn to crack three figures.
The tight-head prop is set to become the ninth All Black to play at least 100 tests, and the third front row player after hooker Keven Mealamu (132) and prop Tony Woodcock (118).
The Motueka native, who turns 31 in December, spent almost a year on the sidelines with an Achilles injury, but is back to his immaculate best after a successful Super 15 campaign with the Crusaders.
Franks may still be without an international try, but his unselfish work in the engine room has shaped him into one of the most influential players in world rugby.
Return of Jordie Barrett
The 21-year-old’s form was off colour during the Hurricanes’ Super Rugby campaign this season, most notably in the semi-final defeat to Crusaders.
With Rieko Ioane injured, Hansen has opted to start the youngest Barrett brother at full-back after omitting him from the 23 last week.
Barrett needs to prove he deserves a regular starting spot, given many believe an in-form Nehe Milner-Skudder should have been named in the starting team ahead of him for this fixture.
At 6-foot-4, the New Plymouth man possesses gas, power, good defence and reliability under the high ball, and has the chance to prove his doubters wrong again on home soil.
Cheika under pressure
An All Blacks win in Auckland on Saturday will seal the Bledisloe Cup for a 16th successive year and may shorten Cheika’s tenure as Wallabies coach.
His record of 25 wins from 49 tests – a 51 per cent record – is only worse than Ewen McKenzie’s 50 per cent win ratio for Wallabies coaches.
Against the All Blacks, Cheika’s side have won twice in 10 matches, one in seven against England and one in five against Ireland.
To make matters worse, a defeat in Auckland will mean six defeats for the Wallabies in the last seven Tests.
However, another lost Bledisloe Cup series is only going to add more pressure to his job. The real question remains whether he will still be in charge come next year’s Rugby World Cup?
Chris Ashton has received a seven-week suspension for his tip-tackle on Rory Kockott during Sale’s pre-season friendly win at Castres last Friday.
Ashton did not accept the charge but an independent disciplinary hearing found him guilty and issued a sanction that mean will miss England’s next training camp in Bristol and the first six games of the Sharks’ Gallagher Premiership season.
“It is an important principle of rugby regulation to prevent injury to others,” panel chair Richard Whittam said.
“Provocation is not a defence to foul play and lifting a player and dropping that player such that his head makes contact with the ground has the potential to cause serious injury.”