The Costa Rican winger suffered a double leg fracture at the start of the year, which ruled him out of Everton's 2013-14 run-in and the 2014 World Cup.
However, Roberto Martinez has brought the 24-year-old back into his side this evening as one of seven changes made by the visitors.
The home side have also made a host of changes, with only six players surviving the cull made by Garry Monk.
Swansea City: Tremmel, Richards, Williams, Fernandez, Taylor, Shelvey, Carroll, Sigurdsson, Dyer, Montero, Gomis
Everton: Howard, Hibbert, Alcaraz, Distin, Garbutt, Gibson, Besic, McGeady, Atsu, Oviedo, Eto'o