The 26-year-old has spent this term on loan at Elche from Pescara and has netted 14 times for the La Liga club.
It is understood that Elche have a deal in place to make Jonathas's move permanent, but they will then look to sell the striker for a big profit.
"This was my last game with Elche. I'll always have a special place in my heart for these fans," Jonathas told reporters after scoring twice in Elche's 3-2 defeat against Athletic Bilbao on Sunday.
Atletico Madrid have been strongly linked with the forward.