Season the venison on both sides with salt and pepper.
In a large skillet, heat the oil over medium-high heat. Add the venison and cook until brown, about 3 minutes per side. Remove from the heat and cover to keep warm.
Add the butter and shallots to the pan and cook, stirring, for 2 minutes. Add the vinegar and stir to deglaze the pan, about 1 minute. Add any juices that have run off from the venison and stir to incorporate. Remove from the heat and adjust seasoning, to taste.
Divide the Celery Root-Pear Puree among 4 serving plates and top each with a venison medallion. Pour the balsamic reduction over the venison and serve.