Premier League rules state you can only take one player on loan at a time from a specific club. Newcastle have Lewis Hall, who is set to make the move permanent next summer.
Hall joined on loan with an obligation to buy, with add-ons taking a potential deal to £35m. Newcastle would have to make the move permanent earlier than planned if they were to pursue Santos on loan.
Chelsea would likely not entertain permanent offers for Santos, a player they rate extremely highly. They announced last January that they had agreed a deal to sign the young star from Vasco da Gama.
He remained on loan with the Brazilian outfit as he couldn’t get a work permit until this summer. Santos played for Chelsea on the pre-season tour to the USA before completing his move to Forest.
