Aprilia technical director Romano Albesiano has credited Andrea Dovizioso with already making an impact on RS-GP development.

Among those to turn down the chance to race for Aprilia this season, the 15-time MotoGP winner subsequently signed-up to take part in a series of tests for the Italian factory.

"It's a very positive experience," Albesiano told the official MotoGP website. "He's such a clever rider. He understands a lot the working of the machine. At the same time he doesn't try to be the engineer himself. He gives us his clear feelings and with his experience he's helping us a lot.

"We've done three tests. One was almost cancelled due to rain, but in the first and especially the last tests he gave us very important information. It's a real pleasure to work with him and he helps us a lot."

Dovizioso is starting his fourth test for Aprilia at Aragon today (Tuesday), which will be followed by Misano on August 5-6 and August 31 – September 1.

With the Misano MotoGP taking place later in September, Dovizioso's pair of tests at the track are fuelling rumours of a possible wild-card. Aprilia told Crash.net that it's not planned "at the moment".

Either way, Aprilia is comfortably on course for its best MotoGP season with the RS-GP.

Aleix Espargaro began the summer break holding eighth in the world championship with 61 points, which compares with a twelfth in the world championship and 82 points by Alvaro Bautista in 2016.

"Aleix is in his best condition. The bike gives him good feeling, he's more confident and everything is working quite well," said Albesiano.

"It's been a very positive first half of the season, the bike showed positive character in terms of engine torque delivery, stability, capability of braking and accelerating. Also cornering is not bad. It's maybe an area where we have to improve but quite okay.

"We are also growing in the engine area but in the last two seasons we have twice made radical changes with the engine, which makes you suffer a bit because every time you have to restart from zero. But the engine configuration we have now has great potential so we will see something much better coming in the future."

Espargaro has equalled the RS-GP's best MotoGP race result of sixth place, twice - including at Jerez, where he crossed the finish line 5.164s from race winner Jack Miller (Ducati), the closest Aprilia has been to the top.

"The performance of the top riders is so close now that identifying a real gap area is not easy. We do a lot of camera recording trackside to understand better where we need to improve," Albesiano revealed.

"It's not easy but of course the more power you have the better it works but in tracks like Sachsenring or Assen it's not so… it's small details, fine tuning where we have to improve."

Aprilia's performances this season have not only caught the eye of Dovizioso but also Maverick Vinales, who is hotly tipped to join Espargaro in 2022 after splitting from Yamaha.

In a reversal of last season's rider search, Aprilia may have a surplus of top-quality options with Dovizioso still harbouring ambitions to race in MotoGP next season after a 'year out'.