Hiroshi Aoyama will switch to the San Carlo Honda Gresini team for the 2011 MotoGP season.
No official confirmation has been made but Aoyama is riding for Gresini at the Valencia test, which starts today (Tuesday).
Aoyama, the last ever 250cc world champion, spent his rookie MotoGP campaign with Interwetten Honda.
But Interwetten has withdrawn from the championship and the only Japanese rider on the grid has been moved alongside 250GP title rival Marco Simoncelli.
Aoyama finished 15th in this year's championship, with a best finish of seventh, having missed six races due to a broken back at Silverstone.
He replaces Marco Melandri, who is moving to World Superbike.