Mauricio Pochettino is not sure why it did not work out at Tottenham for Roberto Soldado, simply saying "football is not mathematics."
Having arrived two years ago among a clutch of post-Gareth Bale acquisitions, expectations were high as Spurs forked out what was a club-record fee that could have risen to £26 million.
However, Soldado failed to reach the heights he scaled during his time with Valencia and is now set to leave north London to return to his homeland.
Sources tell Press Association Sport a £10 million move to Villarreal is in the offing for a player who managed just one Premier League goal last term.
It ends a frustrating chapter for Soldado and those connected to Tottenham, whose head coach Pochettino found it difficult to explain why it did not work for the player in England.
"I don't know," he said. "Football is not mathematics.
"Sometimes there are a lot of reasons that are difficult to explain. I think it wasn't easy for him to adapt his game in England at Tottenham."
The exit of Soldado and Pochettino's admission that Emmanuel Adebayor has no future at White Hart Lane leaves Spurs worryingly light up front.
It means Harry Kane is the sole out-and-out first-team striker at the club right now - a situation the Argentinian head coach plans to remedy by bringing in another centre-forward.
"Sometimes you have five strikers like Liverpool last season and they were sixth in the table," he said.
"Harry Kane scored 31 goals and Adebayor score two and Soldado scored five.
"You never know in football. We need to bring the right profile, the right striker to help the team. It is impossible to guess in football."
Lyon forward Clinton N'Jie looks to be that man, with Spurs understood to be close to securing a reported £10million deal.
"He is another player in the list, in the papers," Pochettino said.
"If you ask me if I know N'Jie, yes, I know N'Jie. He is a player who can play in different positions.
"He is fast, he is a very good player who can play in different positions."