Girona striker Artem Dovbyk has agreed personal terms and given the green light to join Atlético Madrid, sources have told ESPN.
However, the two clubs have yet to reach an agreement for the transfer of Dovbyk to the Metropolitano stadium.
Girona want the player's €40m ($43.4m) release clause to be met, while Atlético are looking to convince them to lower their asking price in the hope of completing the deal in the coming days.
The Ukraine international was last season's top scorer in LaLiga with 24 goals, and the 27-year-old is looking to take a big step in his career after helping Girona to Champions League qualification.
Sources have told ESPN that the player's eagerness to join the Rojiblancos has helped facilitate negotiations between the clubs.
Dovbyk would be the replacement for the departed Álvaro Morata, who joined AC Milan earlier this week.
Sources have told ESPN that Atlético are still trying to sign Julián Álvarez and have held talks to lure the Manchester City forward to Spain.
However, Atlético know they will have to play the waiting game with City unlikely to make a decision on the Argentina international's future until the last days of the transfer window.
Atlético are also waiting to announce the signing of Real Sociedad defender Robin Le Normand.
The club has already agreed personal terms with the Spain international and sources have told ESPN that the two clubs have also reached an deal for the player's transfer.
Atlético want to strengthen their midfield in the summer transfer window following the departure of Saúl Ñíguez to Sevilla.
Among the candidates the Rojiblancos are considering are Chelsea's Conor Gallagher and Real Sociedad's Mikel Merino. Sources have told ESPN that of the two, Gallagher, 24, is best placed to join Atlético.
The England international has been impressed by the positive feedback of Atlético given by compatriot Kieran Trippier, who played for the Madrid outfit for two full seasons.
However, Chelsea's asking price of €40m is set to complicate negotiations between the clubs. The west London club are willing to offload Gallagher but a potentially high fee has stifled interest from Aston Villa and Tottenham Hotspur in the past.
Merino remains Simeone's preferred choice, according to sources, as the Spain international would not require time to adapt to LaLiga as Gallagher would.
Atlético face competition for Merino, though, with Barcelona and Arsenal closely monitoring the player.
Negotiations will also be difficult given Merino's €60m release clause with Real Sociedad.
Atlético, meanwhile, have yet to receive a formal offer for João Félix. The Portuguese winger spent last season on loan at Barcelona.
Sources have told ESPN that Aston Villa have expressed an interest in the player.
Information from ESPN's James Olley contributed to this report.