Neymar's 222m euro (£200m) transfer to Paris-St Germain is "not expensive" but the consequences will cause "problems", says Jose Mourinho.
The Brazil forward, 25, told Barcelona he wanted to leave on Wednesday.
Liverpool boss Jurgen Klopp criticised the proposed world-record deal in light of Uefa's Financial Fair Play rules.
"I thought Fair Play was made so that situations like that can't happen," said Klopp. "That's more of a suggestion than a real rule."
Arsenal manager Arsene Wenger has also criticised the deal by the Qatar-backed PSG, saying: "Once a country owns a club everything is possible and it becomes difficult to respect Financial Fair Play.
"It's a consequence of the ownerships that have changed the landscape completely over the last 15 years. I always plead for football to live within its own resources. The inflation is accelerating. We crossed the £100m line and then a year a later we crossed the £200m.
"It's beyond calculations and rationality."
Neymar's transfer would top Paul Pogba's then world-record move from Juventus to Manchester United last summer by more than £100m.
Mourinho said: "Expensive are the ones who get into a certain level without a certain quality. For £200m, I don't think [Neymar] is expensive.
"I think he's expensive in the fact that now you are going to have more players at £100m, you are going have more players at £80m and more players at £60m. And I think that's the problem."
He added: "Neymar is one of the best players in the world, commercially he is very strong and for sure PSG thought about it.
"So I think the problem is not Neymar, I think the problem is the consequences of Neymar."
Neymar will earn 865,000 euros (£775,477) a week, which will equate to 45m euros (£40.3m) a year before tax.
PSG's total outlay across the initial five-year deal will come to £400m.
Financial Fair Play rules, first implemented during the 2011-12 season, stipulate that European clubs cannot spend more than they earn.
* 222m euros is worth £200m at the time of writing (3 August). With fluctuating exchange rates, it was worth £198m when the story first emerged this week