West Ham have reached a £20m agreement with Swansea to sign Andre Ayew, but must wait for the Welsh club to sign Borja Baston, according to Sky sources.
It is understood that 26-year-old Ghana international Ayew will have a medical with the Hammers this weekend.
Swansea confirmed the signing of experienced forward Fernando Llorente on Friday, but Sky Sports News HQ understands they will only sanction Ayew's departure when they sign another striker.
And it is understood that striker is Atletico Madrid's Baston, who spent last season on loan at Eibar, with the Swans in talks to bring him to the Liberty Stadium.
The 23-year-old has been on loan at a string of Spanish clubs including Murcia, Huesca, Deportivo La Coruna and Real Zaragoza, for whom he scored 23 in 39 games.
The former Spain U19 international starred as Eibar finished 14th last season, scoring 18 goals in 36 La Liga appearances.
Ayew, meanwhile, only joined Swansea from Marseille last summer and was the subject of a £20m bid from West Ham last week, Sky sources reported.
Ayew, brother of Aston Villa striker Jordan, scored 12 goals in 35 appearances for the Swansea.