Chelsea have lodged a bid of £7m to trigger the release clause in Demba Ba's contract.
Newcastle have given the Blues permission to speak to the striker and he will not be considered for the Magpies' Premier League game with Everton at St James' Park tonight.
Chelsea officials held initial discussions with Ba's representatives earlier this week but were unable to reach an agreement on any potential deal.
The Senegal frontman, who joined Newcastle on a free transfer from West Ham in June 2011, already has 13 goals to his name this season and is being pursued by a number of clubs.
Newcastle released a statement which read: "Newcastle United can confirm Chelsea Football Club has made an official offer for Demba Ba which has triggered the release clause in the player's contract.
"The club has given the player permission to speak to Chelsea FC and therefore he will not be included in the squad for tonight's game with Everton."
Chelsea's interim manager Rafael Benitez is keen to add another striker to his squad to provide competition for Fernando Torres, claiming the club's £50m record signing would have no problem with being used in a rotation system.
Benitez has also been linked with moves for Atletico Madrid striker Radamel Falcao and Bayer Leverkusen's Andre Schurrle.
Meanwhile, Blues forward Daniel Sturridge is closing in on a move to Liverpool and is due to attend their clash with Sunderland at Anfield tonight.