The Australian saw his three-race winning streak come to end with a third-placed finish at Misano a fortnight ago, but he still leads Spaniard Jorge Lorenzo by 35 points at the top of the standings.
He put his below-par performance in San Marino down to tiredness, but claims he now feels back in shape after some time off.
"I've managed to rest since the hard race in Misano, where I was totally worn out," Stoner said.
"The hectic schedule we follow had drained me completely and I had no energy, nothing left to give, so I've enjoyed relaxing this past week and getting back to some training."
Even though Stoner is not the Spanish circuit's biggest fan, the Repsol Honda rider is still confident of having a good race.
He said: "The Aragon track is okay, it's not one of my favourite circuits, I feel it could be a little faster.
"We ran well there last year, mainly due to the fact we took a big step in the set up on the bike.
"It will be interesting to go there on the Honda, Dani [Pedrosa] was competitive there last year and I think we can work well there also and expect a good result. We'll get there and see what we can do."
Elsewhere, 38-year old Loris Capirossi will be racing at Aragon for the first and last time as he is due to retire at the end of the season.
Capirossi, who has five races of his MotoGP career remaining, missed the inaugural race at the circuit last year through injury.
"At 38 years old, and a few races away from my retirement, it's funny to think of myself as a newcomer," the Italian said.
"It will be interesting to get to know another track, but of course I'll be starting off with a disadvantage compared to the other riders. I'll give it my all, like always. I want to finish out my career with a smile."
The Pramac Ducati rider has had a disappointing season, partly due to the fact he has not been fully fit since dislocating his shoulder in a crash in qualifying at Assen in June.
He currently sits 17th in the MotoGP standings with just 29 points.