CASEY Stoner has hit out at MotoGP following the Assen race, slamming the grid sizes and calling Yamaha's replacement for Rossi 'a joke'.

The fiery Aussie known for speaking his mind has told reporters that Yamaha's decision to replace the injured Rossi with Wataru Yoshikawa is 'atrocious'. Stoner claims Yamaha should have 'put anybody in that seat, but not a nobody'. Nicely put, Casey.

Ducati's world champ went on to say that grid sizes in MotoGP are 'a joke'. Former MotoGP rider, Toni Elias has also hit out at Moto2, calling it too dangerous.

Stoner's fix? Make the manufacturers, including Suzuki, field more bikes.

Dorna are aiming for 22 bikes on the grid in 2011, but this isn't enough according to Stoner, who went on to say: "They need more bikes on the grid. Suzuki need to be forced to put four bikes on the grid.They’ve got enough money, they’ve got enough chassis.

"It’s just ridiculous, it should be a minimum of four. I don’t understand why companies don’t put last year’s bikes out there like they used to. Put more bikes on the grid, make more opportunities for teams.

"I’m sure there’s a way they can sort it out to run last year’s bikes, then smaller teams can grab a hold. It’s always been like that for years, but now it just seems to have disappeared.”