Old Times at Comiskey Park

Many of my fellow bloggers like to determine the date of game played for baseball cards featuring in-game shots.  Their determination and eye for detail amazes me.  Of course, it also inspires me to try to do the same for some old pictures I have.
Below is a picture of Matt Keough of the Oakland A's warming up before a game against the Whte Sox in Comiskey Park.  I think I have figured out which game this was.
At first, I thought it was from 1981.  However, on second study of box scores, that was a doubleheader in which Keough pitched the second game.  It had a stated attendance of over 25,000.  These two facts made me realize it couldn't be that game.
Looking at the stands, there aren't that many people..  This was back when double-headers weren't played as day-night.  I doubt that many people would have left after game one.  I also don't think Keough would have warmed up prior to the first game if he was starting the second.
This lead me back to the boxscores and ultimately to September 16, 1979.  The Sox beat Keough and the A's 5-2 in front of about 11,000 fans (this also explains the lack of fans in the stands).
My only problem with this theory is the #25 in the A's uniform in the background.  There was no #25 on the 1979 A's, unless it was a coach.
I am disappointed that I could not pinpoint this game, but I am not going to lose sleep or anything.  Maybe I'll have more luck with pictures in the future.  Either way, as always I love the nostalgia of the picture.
Matt Keough in Comiskey Park in Chicago, IL-September 1979.