Getty Images supplied the following information about this photo (as usual, fixed a couple of typos):
Pitcher Ferguson Jenkins #31 of the Chicago Cubs signs autographs for the fans before the start of a Major League Baseball game circa 1973 at Wrigley Field in Chicago, Illinois.
Yes, that’s Fergie. Yes, he’s signing autographs. Yes, it’s Wrigley Field.
1973? Nope. Why?
Well, first, Fergie’s wearing a uniform with a belt. The Cubs dropped belts for the beltless look after 1971 (and didn’t return to belted pants until 1990). So it’s got to be from 1971 or earlier.