Alvaro Negredo's departure from Manchester City to Valencia is mainly down to Financial Fair Play, according to manager Manuel Pellegrini.
The popular striker scored 23 goals in his only season at the Etihad, as 'The Beast' helped City to their second ever Premier League title.
But after City were punished for breaching FFP rules and regulations, the striker, who could sign permanently at the Mestalla next summer after his loan spell, departed back to Spain, leaving Pellegrini with only three senior first-team strikers.
"The decision for Alvaro Negredo to go was for two very important reasons," Pellegrini was quoted by The Guardian.
"The first was that we have the restriction for the number of the players we can use in the Champions League.
"We had one player more, (and) we could not use Alvaro, who was injured, so he was the player who was not going to be on the list."
The fact City were fined £49m and are subject to a reduction in squad size is down to the club overspending their turnover last season.
"It is difficult for me to understand the punishment because the club spent money because they wanted to grow, they finished a new training ground," the Chilean continued.
"They were a small team and wanted to be a big team but now we have that punishment, that sanction, and we have to play with these restrictions."
The 60-year-old said the former Sevilla striker also had a desire to move back to his homeland.
"For him, it was very important because he wanted to go back to Spain, so I thought it was the best decision for the club.
"But the whole transfer all starts from the restriction about the number of players. We have restrictions about the amount of players and the money we can spend."
The move sees City left with only three strikers in their first-team squad, although many managers in the Premier League would love to have the problem of only being able to select from a strikeforce as talented as Sergio Aguero, Edin Dzeko and Stevan Jovetic.
It is understood that City could be ready to target Southampton's English striker Jay Rodriguez in January.