As time runs out on the 2013 season, the scenarios for how things will play out are dwindling. Today, the Pirates play their game in Chicago and it's possible that no matter what happens in this game, it will ultimately have no bearing bearing on how playoff positions or seeding play out.
Obviously the Pirates will want to win this afternoon, because if they do so it could improve their position heading into the weekend A Pirate win and a Reds loss would give the Pirates a two-game lead heading into the weekend series in Cincinnati, which would be huge because it would require the Reds to sweep the Pirates to be able to host the wild card game. If the Reds win against the Mets (12:35 this afternoon), the wild card host will be determined by whichever team wins at least two games in the Pirates/Reds series this weekend regardless of if the Pirates win this afternoon or not.
Meanwhile, a Pirate win would give them a chance to move to within a game of the Cardinals (should they lose to the Nationals this afternoon at 1:45), which would obviously be better than a two-game deficit with three games left. Either way, a Cardinal win tonight at the very least maintains that two-game lead, which would more or less be the end of the NL Central race.
In short: it might not matter at all if the Pirates win this afternoon, but then again it might. Winning would really be the best idea, just in case. First pitch is at 2:20. Francisco Liriano for the Pirates, Jake Arrieta for the Cubs.