Marquez has been out of racing action since the Italian GP in May, after which he decided to undergo complex surgery on the right arm he injured in the 2020 Spanish GP at Jerez.
"As you can see, I'm smiling, which means I'll be at the Aragon GP. Racing, of course," he said in a video posted on Instagram.
"After talking to the doctors and the team, we have decided that the best for my recovery is to continue on the bike, adding up kilometers for next year.
"Doing it in the Aragon GP in front of all the fans is priceless. I'm sure your support will help me go through the whole weekend. Looking forward to Friday and being on the bike."
Since the surgery - his fourth since the accident - the six-time MotoGP champion has been working on his recovery and only just rode his Honda MotoGP bike last week for the first time.
The Spaniard returned to MotoGP action in the post-Misano test, and said he was "suffering more than enjoying" riding the bike again while making positive comments about the improved feeling of his arm following the surgery.
Marquez still completed 100 laps in the test at the Italian venue and finished around half a second off the pace.
"The arm is natural," he said after the test. "It's in its natural position when I don't need to use a lot of strength.
"That means that when I leave the pits or do slower laps, it's fine, but when I use all the strength I still need the muscles to grow and get stronger to stabilize the shoulder and so I can work a lot better.
"On the left-hand corners I felt I was in a more natural position than before. On the right-hand ones, I was lacking strength on the ones I had to push a lot. On the fast section I was losing a few tenths because I don't have full stability yet, but I felt safe all the time on the bike, which is also important.
"We can't forget I only did two weeks in the gym, two days on a bike and then I came here. I haven't had time to get strength, but this test will help me understand where I am, to understand which muscles I have to work on more."
Earlier this week, the Spanish rider took to Aragon's karting circuit with a road Honda CBR 600 bike for another evaluation before announcing his decision to come back to racing.
After his long absence, Marquez sits 15th in the standings with 60 points, still ahead of teammate Pol Espargaro.
Honda is last in the constructors' standings after a dismal season which has included its first point-less race since the 1982 French GP.
