Yonny Hernandez has split from the AGR Moto2 team and will be replaced by American Joe Roberts for the remainder of the season.

Hernandez returned to Moto2 after five seasons in MotoGP, but is only 20th in the world championship with 16 points on the Kalex chassis.

The Colombian's future plans are unknown, with AGR team manager Iker Burutxaga saying only: "Of course, we want to thank Yonny Hern?ndez for the job he has done during the first half of the year and we wish him the best of luck in his future projects."

20-year-old Californian Roberts has been riding for AGR in the European Championship and now gets his chance on the world stage.

"I was surprised to get this opportunity so soon," Roberts admitted. "It's been my dream, ever since I was a little kid to race in the World Championship and I was hoping for next year to get an opportunity, so for me to get it this year is amazing.

"My expectations are basically to keep learning as much as possible and hopefully make some big steps riding with these amazing riders, some of the best riders in the world. If I can come in and learn some more and keep improving with my riding, that would be amazing.

"From the start of this year till now I've learnt so much about this bike and the team seems quite happy with the way I'm progressing. The best thing is to keep that going and we'll see what happens. Thank you to everyone in the team for giving me this amazing opportunity. It's a dream come true."

Roberts is currently fifth in the CEV Moto2 standings, with two podiums, including a second place at the Circuit de Catalunya.

"We're very happy to have Joe Roberts with us for this second half of the World Championship," Burutxaga declared. "After his performances in the first few races of the FIM CEV Repsol, we considered that he was knocking on the Championship's door.

"We think he's a rider that has a high enough level to be among the best and that the earlier he takes that step, will be better for all.

"We are looking forward to seeing him compete with the best riders in the class. He will obviously need an adaptation period, and he'll need to work very hard at the beginning, but we trust his talent and we believe he'll be able to give us some good results."