This drawing presents an example of a so-called garzone study. The artist has drawn one of his workshop assistants (garzoni); in keeping with the master's instructions, he has posed as a figure that the artist wished to study for use in one of his paintings. While the face is given little attention, the gesture of the right hand, the arms, and the legs have been elaborated much more extensively.
The sketch was used for the figure of St Ambrose in the altar painting Madonna di Sant'Ambrogio (private collection, New York). In the painting, the head of an old man was placed upon the figure, which took its place on the right, next to the Madonna and child. This study is clearly a fragment that was originally part of a larger sheet, which showed the entire composition. At the left edge, we can still see the remnants of drapery and shadows belonging to the figure of the Madonna.