Assombalonga has not played since early February, when he had to be stretchered off the pitch during Forest's win over Wigan.
He had scored his 15th Championship goal of the season in the match, his 29th appearance since his summer switch from Peterborough.
The severity of his injury can be seen via the huge incision in his knee in the first photo, but in the fourth picture in the Instagram collage, it is reduced to a sizeable scar.
Assombalonga accompanied the post with a short message conveying his positive mood: "Coming along. God is good"
There is clearly progress in his physical rehabilitation, but there is zero chance of him playing again this season.
Such is the serious nature of the striker's knee injury, it was reported by The Mail after his surgery that he is expected not to even play again in 2015, and take a year to recover.
There is nothing to suddenly suggest he is ahead of schedule, but the striker looks set to keep Forest fans in the loop via his social media page as he continues to work his way back to fitness.