Gus Poyet “would love” to sign Diego Costa from Chelsea but fears Chinese Super League rules regarding overseas players will scupper his plans.
The former Blues midfielder is now in charge of CSL side Shanghai Shenhua and currently has the likes of Obafemi Martins, Fredy Guarin and Carlos Tevez on his books.
He has no room for another foreign addition, with clubs only allowed to field three non-Chinese players at any one time.
That makes a move for Costa unlikely, despite the Spain international being heavily linked with a big-money transfer to Asia at some stage in the near future.
Poyet told talkSPORT: "I would love to [sign Costa] but it will be very difficult for us because of the quantity [of non-Chinese players] we have got. There are three who are playing.
“There would have to be a massive change to the structure of the club to be able to bring Diego here.
“I don’t know if it’s going to happen, I would never say ‘no, never’, but I would say it would be very difficult for him to come here.”
The new rules introduced by CSL authorities could also force another high-profile Chelsea star to look elsewhere as he contemplates his next move, with John Terry about to become a free agent.
It appeared at one stage as though the ex-England captain was destined to head to China, but Poyet believes that the veteran defender will now explore other options.
He added: "If you asked me in December before they changed the rules, I would have said straight away he was coming. I was 100 per cent sure. No doubt.
"But with the new system, it is special to buy a defender. The mentality has changed a lot because they [Chinese teams] are looking for players to make the difference up front - the ones that are going to bring people to the stadium."
Costa and Terry have helped Chelsea to the Premier League title this season and will be looking to complete a double in Antonio Conte’s first campaign at the helm when they face Arsenal in the FA Cup final.