The Finn spearheaded Caterham's race lineup until this year, when the team opted for the sponsored drivers Giedo van der Garde and Charles Pic.
But Kovalainen, who appeared in Friday practice for the green-clad team in Bahrain and Barcelona, is back in the paddock at Silverstone this weekend.
Turun Sanomat reports rumours the 31-year-old could be drafted back into Caterham's race lineup, at Dutchman van der Garde's expense.
Kovalainen said: "Nothing has been agreed, so do not try to guess.
"But I am ready to go in all respects, and yes I would rather be here to be racing than not," he added.