This image depicts Heavyweight boxing champion John L. Sullivan meeting the Boston American’s team captain, Jimmy Collins by the dugout at Huntington Grounds in Boston during the 1904 season. We can identify the year by the cap Collins is wearing. There is a better know image, likely taken at the same session of Collins and Sullivan sitting on the bench in the dugout.
It is possible, perhaps likely, that the rotund player standing to the right is Cy Young.