I've since had the pleasure of viewing other pictures from this set. This is definitely a "blackface" player in a medicine show. I have good reason to believe that this is Tommy Scott from Doc Chambers' Medicine Show. Scott played guitar, sang, performed in blackface, and did a ventriloquism act (note the ventriloquist dummy in front).

This is more likely to be a medicine show. A minstrel show performer would be much more elaborately costumed, and would probably (though not always) be a white performer in blackface.

Medicine shows often featured music and comedy playlets, almost always including a black stock character, and black musicians, all costumed much more rustically (as here). Indians were most often employed to lend credibility to the medicine's origins in the "natural healing arts of the Red Man".

Medicine Shows were in the 1800s, mostly, and sold medicine--snake oil--and tended to use Indians. This appears to be a minstrel show instead?

[The caption cards for this and a similar photo both say medicine show. - Dave]