MotoGP rookie Mika Kallio is targeting at least a top six finish during his big chance as a factory Ducati rider.

The young Finn will switch from the satellite Pramac Ducati team to the factory Marlboro squad as a temporary replacement for 2007 world champion Casey Stoner, who will miss the next three races as he seeks to shake off a mystery energy-sapping illness.

"I want to say thanks to the Ducati Marlboro Team and also my 'old' Pramac team for this opportunity, it is a really great chance for me and now I need to get results," said Kallio.

"They [Ducati] called me on Monday morning and said the situation is this: Casey will stay at home and not come here. They asked if I can take his seat and replace him.

"I said everything is okay for me, if it is okay for my old team. Paolo [Campinoti, Pramac boss] was happy for me to do it and it all happened really fast... It is good for me, but I hope Casey will be better after these three races and then I will go back to Pramac."

Kallio is still to beat his two eighth places at the first two rounds of the year, but has been challenging for sixth on several occasions - including at Assen, when he crashed just a few corners from the finish and had to sit out Laguna Seca due to a nasty finger injury.

"I need to concentrate now. These are three really important races and my plan is to do the best result I can and see where we are," said the former 125 and 250GP title contender. "First I need to finish the races. I think our level is somewhere around fifth or sixth place and now, with this new team, we can do something better. Then, after three races, we will see where we are."

Kallio will be riding alongside 2006 world champion Nicky Hayden, who has taken a best finish of fifth so far this season.

Hayden is 13th in the world championship with 47 points, while Kallio sits 15th with 34 points. Double 2009 race winner Stoner is presently third with 150 points.