It appears that this drawing remains part of the collection of the Uffizi Gallery in Florence, just one of a large number of Michelangelo's work that they possess. An early sighting of this sketch was in Illustrations from The Life of Michael Angelo by Romain Rolland from 1912.
This work is not displayed prominently in the gallery and is considered less significant than some of the other Michelangelo drawings that they possess. You will also find sketches by other famous Renaissance artists here too, and not just other Florentines.
Their selection of Raphael drawings, for example, makes a visit to this prestigious venue worthwhile almost on their own. Having played such a significant role in the Renaissance, it is pleasing to see the city of Florence still retaining many of the highlights from this influential art movement which also took in many other disciplines such as literature, archtecture and science.
Michelangelo would most probably have brought a model along for this particular portrait and perhaps finished it off at a later date. It is difficult to conclude too much from this artwork because so little information on it is available, such as related artworks or where the figure may have been seen again.