Here's my breakdown of the rosters for the Cardinals-Braves game. Let's move over to the American League.
DH -- Jim Thome
With the Orioles pushing for the AL East title and/or home-field advantage in the wild-card game until the season's final day, Showalter was left with the unfortunate result that it's Joe Saunders' turn in the rotation. This is about the worst possible matchup for the Orioles: A left-handed fly ball pitcher against a lineup with right-handed power where the ball zooms out to left field. It's no surprise that Saunders is 0-6 with a 9.38 ERA in six career starts in Texas (although the last one came in 2010). He has allowed 13 home runs in 31 2/3 innings in Texas, so this has danger written all over it. Showalter should be happy if he can get three or four innings with minimal damage from Saunders.
In fact, Showalter should consider the old Jim Leyland maneuver of starting Saunders and baiting Ron Washington into his two platoons. (In the 1990 NLCS, Leyland started Ted Power, a reliever who hadn't started all year, then went to lefty Zane Smith in the third inning.) Showalter could go early to Hunter (one run allowed since moving to the bullpen in September) or Steve Johnson, either of whom could go multiple innings.
Offensively, the Orioles struck out the third-most times in the AL and they face Yu Darvish, who ranked second among AL starters in K's per nine. The Orioles don't get much offense from second base but don't really have any good pinch-hit options on the bench. Chavez is around as a pinch-runner/defensive replacement for Davis. Overall, this is easily the weakest bench of any of the playoff teams. Showalter has little choice but to ride his starting nine and hope they connect on a couple long balls.
The Rangers elected to go with 11 pitchers, and while it's unlikely to envision a scenario where they'll need all 11, it certainly gives Washington maximum flexibility with bullpen usage and matchups. Truth is, the bullpen is a huge question mark right now, especially with Mike Adams injured and Ogando and Nathan both a little shaky down the stretch. Harrison started Tuesday and Holland pitched in relief on Wednesday, so it will be interesting to see who the long man would be if Darvish gets knocked out early. I can't imagine Washington has a lot of faith in Feldman or Oswalt, so I assume Harrison would be the guy, even on two days' rest.
Washington's hope is for Darvish to pitch deep into the game and then turn it over to Ogando and Nathan. Other than a possible lefty-lefty matchup on Chris Davis or Jim Thome, if any other pitcher gets in the game it probably means Darvish struggled.
With Saunders starting, that means the Rangers likely start Soto behind the plate and Napoli at first, with Gentry in center field and Josh Hamilton in left. The Rangers could also decide to start Murphy in left, leaving them a little less vulnerable in case Showalter decides to go with the Leyland maneuver. (As I write this, the starting lineups haven't been announced.)
The Rangers only used 19 position players all season and three of those had fewer than 20 plate appearances (including third catcher Martinez). I suppose they could have kept Mike Olt or Brandon Snyder, but the likelihood of needing a 15th position player in an AL game is pretty slim.