The Negro League team Jackie Robinson actually played for was the Kansas City Monarchs (who so dominated African-American baseball they were often called the "Black Yankees"), not the fictitious "Black Panthers".
Harry Shannon's character is listed as "Charlie" in the end credits cast of characters. However, he plays the role of "Frank Shaughnessy", President of the International League.
The scene where Jackie's clothes are no longer hanging on pegs and have been moved to a proper spot was bumped to five minutes from the end, when they are close to winning the pennant. It should have been shortly after he joined the Dodgers.
After the locker room scene where they are talking about contracts, the Panthers are playing the Eagles. Batter number 1 is up to bat, the pitcher throws the pitch, the ball is clearly over the batter's head, the batter does not swing, yet the umpire calls strike 2.
Late-1940s cars can -be seen in the 1928 scenes.