Pittsburgh Pirates First-Place Eliminiation Scenario
Pittsburgh must win 25 more games (38 total) to avoid elimination from first place.
Here are the final standings in a scenario in which Pittsburgh finishes in first place with 38 wins:

Team             W	L	PCT	GB
Pittsburgh       38	124	0.235	0.00
Milwaukee        38	124	0.235	0.00
Cincinnati       37	125	0.228	1.00
Chicago          37	125	0.228	1.00
St. Louis        36	126	0.222	2.00

Tie breakers
Pittsburgh wins the series with Milwaukee 8 games to 5

To construct the scenario, we start with the current standings in the division:
Team             W	L	GL	PCT	GB
Milwaukee        14	8	140	0.636	0.0
Chicago          14	9	139	0.609	0.5
Cincinnati       13	10	139	0.565	1.5
Pittsburgh       13	11	138	0.542	2.0
St. Louis        10	14	138	0.417	5.0

Next, we show how the remaining series of games plays out in the scenario:

Chicago currently has 0 win(s) against Cincinnati and 0 loss(es).
Chicago wins 6 additional game(s) against Cincinnati and loses 7.
Chicago loses the series 6 games to 7.
Chicago wins 0 additional game(s) against teams outside the division and loses 87.

Chicago currently has 0 win(s) against Milwaukee and 0 loss(es).
Chicago wins 11 additional game(s) against Milwaukee and loses 2.
Chicago wins the series 11 games to 2.
Chicago wins 0 additional game(s) against teams outside the division and loses 87.

Chicago currently has 0 win(s) against Pittsburgh and 0 loss(es).
Chicago wins 6 additional game(s) against Pittsburgh and loses 7.
Chicago loses the series 6 games to 7.
Chicago wins 0 additional game(s) against teams outside the division and loses 87.

Chicago currently has 0 win(s) against St. Louis and 0 loss(es).
Chicago wins 0 additional game(s) against St. Louis and loses 13.
Chicago loses the series 0 games to 13.
Chicago wins 0 additional game(s) against teams outside the division and loses 87.

Cincinnati currently has 1 win(s) against Milwaukee and 2 loss(es).
Cincinnati wins 2 additional game(s) against Milwaukee and loses 8.
Cincinnati loses the series 3 games to 10.
Cincinnati wins 0 additional game(s) against teams outside the division and loses 90.

Cincinnati currently has 0 win(s) against Pittsburgh and 0 loss(es).
Cincinnati wins 8 additional game(s) against Pittsburgh and loses 5.
Cincinnati wins the series 8 games to 5.
Cincinnati wins 0 additional game(s) against teams outside the division and loses 90.

Cincinnati currently has 0 win(s) against St. Louis and 0 loss(es).
Cincinnati wins 7 additional game(s) against St. Louis and loses 6.
Cincinnati wins the series 7 games to 6.
Cincinnati wins 0 additional game(s) against teams outside the division and loses 90.

Milwaukee currently has 0 win(s) against Pittsburgh and 2 loss(es).
Milwaukee wins 5 additional game(s) against Pittsburgh and loses 6.
Milwaukee loses the series 5 games to 8.
Milwaukee wins 0 additional game(s) against teams outside the division and loses 96.

Milwaukee currently has 3 win(s) against St. Louis and 0 loss(es).
Milwaukee wins 9 additional game(s) against St. Louis and loses 1.
Milwaukee wins the series 12 games to 1.
Milwaukee wins 0 additional game(s) against teams outside the division and loses 96.

Pittsburgh currently has 0 win(s) against St. Louis and 0 loss(es).
Pittsburgh wins 7 additional game(s) against St. Louis and loses 6.
Pittsburgh wins the series 7 games to 6.
Pittsburgh wins 0 additional game(s) against teams outside the division and loses 88.

# Pittsburgh Pirates' magic number
# Pittsburgh's magic number
# Pirates' magic number
# MLB Playoff Race