Stevenson misplaced his WBC light-heavyweight belt on Saturday evening after being knocked out within the 11th spherical by Oleksandr Gvozdyk.
The Canadian was carried from the ring on a stretcher and brought to hospital, the place his situation was initially described as vital.
However Michel posted on Twitter on Sunday to say the 41-year-old had just lately improved.
“Replace on Adonis @AdonisSuperman: The state of Adonis has gone from vital in the direction of steady from yesterday to right this moment which is comparatively excellent news. He’s in managed sedation to facilitate his recuperation,” Michel wrote. “His household, his spouse Simone and Groupe Yvon Michel want to thank the many individuals who’ve taken the time to ship comforting messages. New info shall be printed as we get it. No different feedback shall be made till then.”