According to Sky Sports, the West Brom player has a £16 million release clause in his contract due to the club getting relegated from the Premier League last season.
However, Newcastle may not have the funds to meet that clause, unless they are able to cash in on their unwanted attacker Aleksandar Mitrovic.
Fulham want to sign Mitrovic, but they are hoping to get him on a season long loan deal. Newcastle want to sell, so they can use the funds to improve the squad.
Newcastle manager Rafa Benitez already admitted that his club must "wheel and deal" to ensure they can improve the squad. Signing Rondon is only possible if funds are generated from a sale.