This next one is a bit tougher because bench slots in the postseason come down to some philosophical choices. Robbie Grossman hasn't been good this season, but he does seem to be the most likely guy to get the first outfield bench spot. The question after that comes down to whether or not to carry a fifth outfielder and that is where the problem in carrying Travis Jankowski comes in.
Jankowski hasn't helped his own cause lately as he has just two hits over the last month, but the fundamental problem is that carrying that many outfielders just doesn't have much value in a playoff series. Ezequiel Duran isn't a good defender, but he can hit and more importantly, he can play a bunch of different positions including the outfield. That flexibility makes using a bench slot on him make more sense than bringing Jankowski along to be a defensive replacement.
Josh H. Smith
Much of what was said about Jankowski above applies to Josh Smith here as well. Yes, Smith can play in the dirt at multiple positions which makes him more likely than Jankowski to make the cut, but the Rangers still have Duran to fulfill that role in a pinch and can petition the commissioner for an injury replacement if a guy gets hurt.
The fundamental problem with Smith is that he can't hit. In 230 plate appearances this season, Smith has slashed .187/.307/.332 which is decidedly not great. If something happens and Texas needs to add him after the fact if an infielder gets hurt, so be it. However, carrying him from the start of a playoff series is a waste of a roster spot.
Going back to the bullpen again, the Rangers have a bunch of southpaw relievers and frankly, not all of them need to be playing in the postseason. One name in particular that jumps out as a guy that needs to be culled for the playoffs is Cory Bradford.
Ultimately, this decision comes down to the question "when would you be comfortable having Texas put Cody Bradford in a playoff game?". He has a 5.30 ERA and has given up a ton of hard contact this year with even opposing lefties having an .800 OPS against him. If the answer to the above question is only when the outcome of the game is already decided (which seems likely), the Rangers have better arms that can fulfill that role and Bradford's spot needs to go to someone else.