Just over a year ago, KTM test rider Mika Kallio feared his career might be over after a serious knee injury during a wild-card appearance at Sachsenring.

But in a situation unimaginable as he lay in the hospital, Kallio has now been called-up to finish the season at the factory MotoGP team, with a chance of staying alongside Pol Espargaro for 2020.

"It's a really special moment for me," Kallio said at Aragon on Thursday. "It's more than a year since I was last on the bike in a race. There have been some hard moments because of the bad injury on my right knee, which was close to stopping my career.

"It was five months off the bike, just before Christmas was my first time back on the bike. The rehab was a little faster than expected, so I was one month early. But it wasn't an easy time. But now I'm back again. So it's just something to enjoy for the moment.

"Basically, there's no pressure from the team-side for results. Everyone knows it's not an easy situation to come back like this. It'll definitely take some time to adapt my feeling to race mode again."

Kallio's big chance follows KTM's split from Johann Zarco, who initially looked set to leave at the end of this season, but has now been sent home on full pay for the remaining six races of 2019.

"For sure all the bikes have a DNA and different characteristics," Kallio said. "[Zarco] came from Yamaha, completely different, and you need to change a lot the feeling and adapt the style for the bike.

"I know that he worked a lot to change, even his riding style, but in the end it just didn’t match. It's hard to say why. Everybody was helping him and I tried as much as possible, just to give some small advice about what I did when I came to KTM. But in the end it doesn't work."

Espargaro, who took the KTM to its best qualifying performance of second last weekend at Misano, said of his team-mate's early departure:

"It's very difficult when you are not adapting to a bike and then you try to force and try to train and nothing is coming. At the end we are in MotoGP world where everything is so professional and everyone is super fast and super fit.

"You need to adapt to the bike very fast, or you lose your train and for sure I feel really sorry for Johann because he is a good guy.

"But the situation has been very tricky for him all year and in the end I think it’s the best solution for both parties. For Johann to rest a little and catch a new opportunity and for the team to continue developing with Mika.

"I think Mika's going to be fast, honestly. Already he's done wild-cards with us and was very strong until the injury at Sachsenring."

Kallio, who gave the RC16 it's race debut at Valencia 2016, has spent this season sharing KTM testing duties with Dani Pedrosa.

"First of all it was really good to have him aboard and like everyone knows he has a lot of experience from the past and from Honda he has a lot of information to bring," Kallio said of the 31-time MotoGP race winner.

"For me it was also a nice opportunity to see how he is working, his feeling on the bike and also good to see that basically his feeling, needs and what he is looking for from the bike was quite similar to me. So it was quite easy to understand and work with him."