The veteran, Montreal's best and most experienced centre back, said he requested a trade to a winning team during the season because he felt unmotivated with the Impact sitting in last place with no hope of making the playoffs.
He also felt the team had no specific plan to improve for next season.
"At 35, if you don't have motivation, it's hard," said Ferrari, who will turn 35 on Dec. 5. "One month ago, when a playoff team called the club for a trade, I asked to be traded because I thought it was a moment for me to find new motivation, a new experience. And I felt my job in Montreal was done."
Ferrari did not name the team that requested him. At the time, he was told he was too important to the team to be traded.
He was informed Friday that his option for 2015 would not be picked up. Also let go were defender Futty Danso and midfielders James Bissue and Zakaria Messoudi.
"The difficulty in having these players return lies in our salary cap," coach Frank Klopas said in a statement, adding that more roster changes were expected.
Klopas also wants more speed on defence and said he has two plans in the works on changes for next season, although he did not elaborate on them.
Ferrari said he was disappointed that the team cut him without a proper send-off, so he put out word that he would meet with the media on his own; at the posh Ritz Carlton hotel, no less.
"I think I deserve a better goodbye," he said. "That's why I decided to have this conference, because the fans showed me a lot of respect. They loved me in Montreal and I felt they deserved that."
Ferrari avoided any direct criticism of Klopas or of Impact management, but said he didn't want to endure another losing season.
He hopes to find another team, possibly in MLS. If not, he will consider retirement. He said one team, which he didn't name, has already shown interest.
"I'm not rushing because, if I continue to play, I'd like to be part of a big project, a winning team that's going to win in a short time because I'm 35," he said. "If not, I can easily retire. Florida is waiting for me."
Ferrari, an Algeria-born Italian, joined the Impact for its expansion season in 2012 as part of a wave of former Serie A players that included defence great Alessandro Nesta, who retired after the 2013 season, and striker Marco Di Vaio, who has also hung up his boots.
The Impact missed the playoffs in his first year, but was among the top teams in MLS in 2013 before a second half collapse. They managed to clinch the fifth and final Eastern Conference playoff berth by the slimmest of margins, but were beaten 3-0 in Houston in their only playoff game.
The team carried its weak finish into the 2014 campaign under Klopas, its third coach in as many seasons. The positives from the season were winning a second straight Canadian Championship and reaching the quarter-finals of the CONCACAF Champions League.
Ferrari said he asked Impact management about plans to improve the team for next season but "no one was in a place to give me an answer.
"You lose Marco, for example. I'm sure the team is going to try to replace him, but you want to know right now who's going to be in Marco's place because the (Champions League) game is in February, not in June. And nobody can answer.
"For me, that's the signal that there's something not clear. And I can't wait. The last three months here, we played with no motivation. I come from a different school where to you play to win or not to go in second division. In MLS, it's different. You can play six months for nothing."
The former Inter Milan defender expects the Impact to be somewhat better next season because player changes, including the signing of designated player Ignacio Piatti, were made during the 2014 campaign. But he doesn't want to wait through the rebuilding process to have a chance at a championship.
In mid-season, the Impact removed former player and coach Nick De Santis as technical director and gave Klopas full control on personnel moves, with job security through the 2015 season.
Ferrari wished Klopas luck.
"I think he's trying hard to make it work,"said Ferrari. "He has a lot of experience in this league, but experience isn't everything. You also need a team.
"I want to say the team needs to improve. I don't think there's anything wrong with saying that. Everybody knows. Now Klopas has the key to the team and the choice of players, so I think next year is going to be a big challenge for him. But I'm sorry, I can't be part of this team because without a program, a plan, I can't. I needed an answer and I didn't get an answer."
Ferrari was an outspoken player in his three seasons, speaking his mind where other players preferred more diplomatic answers about the team's struggles. He was the first to criticize the team's lack of significant player moves last winter, for instance.
But he disagreed with post-season statements from some teammates that the squad lacked unity and leadership in the locker-room.
"I think it was more about the results," he said. "We were always making the same mistakes and we didn't improve. That's when I started to feel empty and without motivation.
"We all have to take responsibility. I don't want to point a finger at any player or the coach. As a group, we didn't work well in many aspects. And we saw the results on the field."
Ferrari also said that Italian club Fiorentino tried to buy him two years ago but was turned down by the Impact. Asked if he would have gone, he said: "Maybe."