Tai Woffinden was operated on for several hours on Sunday evening for multiple fractures and a chest injury after the serious crash in a training match with his Polish club team Stal Rzeszów.
The 34-year-old Briton, three-time World Champion who also rides for Swedish Västervik, has since been lying sedated.
His family has now spoken out for the first time.
"For the time being, it's tough and we're focusing on one moment at a time", writes his wife Faye Woffinden on Instagram on Wednesday morning.
She also says it's too early to give any further updates on the injury situation, but thanks for all the support the family has received.
"During this extremely difficult time, it shows that we don't have to go through this on our own. We're still processing everything and need a little more time to understand how everything stands before we give any further updates".