Spalletti told reporters after their 2-2 draw in the Derby della Mole against Torino that the squad lacks the personality required to compete at the highest level and that responsibility for the collapse lies with him as much as anyone.
The match itself was played in extraordinary circumstances. Clashes between Juventus and Torino ultras outside the Stadio Olimpico Grande Torino caused a delay of more than an hour to the scheduled kick-off. A Juventus supporter was taken to hospital in critical condition. Bianconeri fans left the stadium in protest once the match eventually began.
On the pitch, Juventus led 2-0 and then surrendered the advantage in a second half that was already mathematically irrelevant. Roma and Como both won simultaneously, eliminating any possibility of Juventus finishing in the top four. They end the campaign in sixth place with 69 points, qualifying only for the Europa League.
Spalletti was direct on the team's character deficit.
"I'm the coach who has to examine what happened. We had the game in our hands — it's in these games that you see the people's character and how we are made inside. Those without enough personality can't play for Juventus. Those with doubts, if they stay in them too long, become doubtful. If you make a choice, you show what level you are at."
He criticised the squad's inconsistency across the season while defending the players' effort.
"These players have done many things well across large stretches of the season and I thank them for what they have done. But we have paid a heavy price in some matches. Missing more than one penalty that was decisive for the table — that is what penalises you."
He expressed confidence in the club's stated commitment to rebuilding.
"(Damien) Comolli has said we will build a competitive squad. (John) Elkann is fully convinced. He is the boss who gives us direction, so we go forward with confidence in trying to build a stronger team, even if this one has not done badly — something will need to improve."
On the violence before kick-off, Spalletti used his platform to condemn what had happened while criticising Torino's pre-match statement that had suggested banning Juventus's black and white colours from a section of the stadium.
"A society that lives with violence has no future. I send greetings from everyone to the fan who is in hospital. Banning black and white in a section of the stadium seems an absurd decision. The problem is those who say certain colours should be excluded."
Juventus will play Europa League football on Thursday evenings next season. They finished where Spalletti found them when he arrived.