"What we had in pre-season was probably the worst put-together squad in the history of the league," the former New Zealand international said in looking back at the start of his managerial tenure with the underachieving club.
"In the history of the league. It was that bad. It was actually terminal."
That opinion was shared by coaches and others around the league, Nelsen is quick to add.
Nelsen and team president Kevin Payne, who was fired in September, attacked the roster like Jason Voorhees in a "Friday the 13th" movie.
In its 2013 transactions section, the MLS website lists 26 players going out the door at Toronto FC and 27 coming in.
A tangle of poorly conceived contracts exacerbated the roster problem the Kiwi inherited. Nelsen maintains that when he came on board, judging from discussions with others in the league, the only Toronto player that drew interest from any other club was attacking midfielder Luis Silva.
"There was only one and even that was for cover (as a reserve)," Nelsen said in a recent interview with The Canadian Press.
"And now, a year on, there's probably about 15," he added.
Silva is not one of them, unfortunately. "I wish he was," said Nelsen.
Payne dealt Silva to D.C. United amidst talk a replacement was coming. It never quite happened.
Toronto's past contracts were so bad that allocation money was used to pay down bad deals rather than improve a roster framed by the league's salary cap. As a result, the team often found it had to sell its best players to help pay for the bad contract that no one else wanted.
Nelsen says he feels for the seven managers in the six seasons before him. He believes their problems snowballed as the pressure to right the TFC ship intensified.
This season, he said, was time to put on the brakes.
"At some stage you've just got to stop, you've got to stop the bleeding and you've got to take two or three steps back and just go 'Hang on,'" he said. "You take the criticism, you take the hits with it and you take the heartache because you're going to have to. You clean it up and start again."
The 2013 season produced a 6-17-11 record for Toronto, good for 17th in the 19-team league. But where Nelsen once saw little more than liabilities, today he sees a young roster full of assets.
So far, Toronto has parted ways with seven players. It did not pick up options on striker Robert Earnshaw and midfielders Bobby Convey, Michael Thomas and Darel Russell, and strikers Danny Koevermans and Justin Braun and goalkeeper Stefan Frei are out of contract.
"There's going to be changes, of course," said Nelsen. "But the changes that are going to get made are only to come in as starting players for our team, that will start on the majority of teams in MLS. Those are the only players we're looking to bring in."
The franchise, which scored just 30 goals in 34 games this season has embarked on a much publicized search for two marquee strikers.
Nelsen and GM Tim Bezbatchenko, a young brainiac hired away from the league front office and described as "wicked smart" by MLS commissioner Don Garber, are also looking for two or three "hardened" MLS players.
Would Toronto be interested in former league MVP Dwayne De Rosario at the right price?
The 35-year-old De Rosario, Canada's all-time scoring leader, parted ways with D.C. United after the regular season.
"Obviously at the right price is the big key but also it's how you'd see his position on the team. I do know there's a bit of history here as well," Nelsen said, referring to a salary dispute that led to De Rosario leaving Toronto in 2011.
"So there'd have to be a lot of things that have to fall in the right place, but he's been such a good advocate for the league and Canadian soccer to tell you the truth. You'd like to see him keep going."
As the January transfer window approaches, Toronto has been linked to the likes of star strikers Alberto Gilardino, Jermain Defoe, Samuel Eto'o and Gilberto.
Nelsen will only say his wish list is much longer.
"Is the list 50 names long? Of course it is. It's huge. We try and cover our bases."
I can't think of how many players we've looked at," he added. "There's so many.
"What the reality is is you never probably get your No. 1 and you probably don't get your No. 2, you probably don't get your No. 3, No. 4, so you need to have a list."
MLSE boss Tim Leiweke, who helped bring David Beckham to the Los Angeles Galaxy, has said there can be no room for error in signing designated players.
For one, there's the cost.
Even if Toronto were to sign a striker at the low end of the pay scale in the English Premier League, Nelsen reckons a four-year package with a transfer fee would be in excess of US$20 million.
Once a home to fading foreign stars, the North American league is now attracting younger marquee talent. But the competition is fierce.
"At the moment it's hard to compete for the 25- to 28-year-old players in Europe," said Nelsen. "It's hard to compete with the lure of Champions League football and the lure of the stature that European football has.
"If we want a 28-year-old, so do 10 European teams who can pay what MLS considers massive money but is considered over there as just par, average money," he added.
Plus finding the right player for MLS is a delicate balancing act, involving age, desire and price just to name a few of the factors.
"Just because he might be a very good player in England or Italy or Spain, it doesn't mean he's going to be a good player in MLS. MLS is unique, it has different variables that not many players are used to."
Nelsen credits a generous owner in MLSE, which has agreed to dig deep to finance designated player acquisitions. He hopes the new DPs will be at training camp come January.
"Good ones are always hard, they always take time," Nelsen said of the search for talent. "It's like your missus, I bet you it took time to get her. The good ones always take a lot of courting.
"If it's taking time, take that as a positive."
The TFC manager knows from personal experience what a star striker can do for a club.
Blackburn Rovers were fighting relegation when Nelsen joined the Premier league side in 2005 from D.C. United.
Then the team signed Welsh striker Craig Bellamy, who scored 13 goals in helping Blackburn to sixth place.
When Bellamy moved to Liverpool, Benni McCarthy took over and finished second in scoring in the Premier League in 2006–07 with 18 league goals. Blackburn was 10th.
In 2007-08, Blackburn finished seventh as Paraguayan hitman Roque Sante Cruz scored 19 goals to finish fourth in scoring behind Cristiano Ronaldo (31 goals), Fernando Torres and Emmanuel Adebayor (24 goals).
The next season, Santa Cruz scored just four goals and Blackburn finished 15th.
"All of a sudden those guys would go and we would drop down (the standings)," Nelsen said of the strikers. "And that's the difference, having a striker that scores that amount of goals is the difference between which end of the table you're going to look at."
Some ask who will service the new strikers.
Nelsen says his young midfield has the goods but is still developing. To that end, he will likely bring in some veteran talent to bridge the gap as they grow.
But he says elite forwards make everyone better.
"Everybody talks about service and all that but good strikers, they make everybody else look better. That's what good players do."
And Nelsen knows star power, having played with the likes of Santa Cruz, Gareth Bale and Luka Modric.
"Even at that level, the game was easy for him," he said of Bale. "No disrespect to Tottenham, you knew he was going to a Real Madrid. He was that level.
"When you see it first hand, you kind of wonder why you're playing the game to tell you the truth, it's that humbling."
The standings may not show it yet, but Nelsen firmly believes Toronto is on the move.
After inheriting "probably the worst (team) in history in terms of everything," Nelsen is proud to point out that the young roster that finished out the campaign kept training after its season was over.
"I've been on teams where we haven't made the playoffs and the sun decks are out. It's an absolute joke, it's embarrassing."
Not those who survived a tumultuous season to remain on his current Toronto squad.
"What I really like about this team is we have a core group of guys now that we're not going to move, they're going to be staying around here for ages. Hopefully."
At 36, Nelsen is supremely comfortable in his own skin.
In a season of turmoil, he outlasted Payne — a longtime league executive with a choice of championship rings and a sizable Rolodex — and has the confidence of Leiweke.
Not the most gifted defender in the world, the hard-working Nelsen was nevertheless savvy enough to survive in the cauldron that is the English Premier League.
He knows what it is like to be a fan favourite, and to be shown the door in his playing career.
That shows in his young managerial career. Nelsen has proved to be a steely customer.
Irate that a rival assistant coach boasted that he learned of TFC's starting lineup from local reporters' tweets at practice, he restricted access to training sessions to the league minimum. Plus he often took his team to a field at the other end of the training ground, leaving reporters far away from the action.
He has managed to keep his private life private, although we do know he has a wife and family, even a vinyard (RN Wines) plus an assortment of homes around the globe.
During the season, he showed a ruthless side to player personnel decisions.
But he also refused to air the team's dirty laundry in public. And there was plenty on and off the field.
"There's so many people out there that's going to tell them if they made a mistake," Nelsen said of his players. "They don't need me telling them publicly because that makes me feel better. Because that's all it really is, isn't it?
"Whenever I hear a coach do that, it's just deflecting the criticism, onto the player and not himself. ... For me, I'll take all the criticism and any of the praise should always go to the players and not to me. Because I don't need it, don't care about it, don't want it. But I know criticism affects players and I know praise affects players positively."
He is all about putting the team on the right track.
Just don't expect too much candour when Nelsen is in front of a microphone.
"In all honesty here, do you really think I'm the same person in front of the media and in front of people I don't know as I am in the changing room with the guys I have to be with in day in and day out?" he asked with no shortage of incredulity.
"I mean it's professional football, this is proper stuff, this is not a Sunday kickaround. There's ripple effects of whatever you say in the media."
Nelsen isn't above showing the media the back of his hand, at least verbally. On more than one occasion this season, he essentially told beat reporters covering his team they did not know what they were talking about.
But he always did it in style, even when called on it by a reporter.
"Do you need a hug?" a smiling Nelsen asked, then wrapped his arms about the scribe.