I'm using the Pirates as an example, but it is a question that could be posed for any team in a similar situation.
So the Pirates are in the wildcard game playing the Cubs. Both teams have their respective aces going (Cole and Arrieta). The Pirates find themselves down 1-0 in the bottom of the 4th. The bases are loaded with 1 out and Cole is coming up. Cole has only thrown 60 pitches. Do you let him hit?
Obviously their are a lot of variables at play, but the Pirates would have a complete bench so they could throw a left handed hitter out there to pinch hit. The other important note is that you are allowed a unique roster for the game. So the Pirates can have a slew of relievers at their disposal along with several guys capable of pitching multiple innings.
So does Cole bat?