In this age of parity, no team enters the postseason without at least one significant flaw. Let's look at the four American League teams and how their flaws may affect their postseason run.
Baltimore Orioles: Low OBP
The Orioles led the AL in home runs but ranked just 11th in the league in on-base percentage. In other words, they rely on home runs to generate a large percentage of their offense.
You would assume that the rate of home runs goes down in the postseason as teams face better pitching. While that's been true the past two postseasons, it's not always the case:
2013 regular season: HR every 35.6 at-bats
2013 postseason: HR every 45.3 at-bats
2012 regular season: HR every 33.5 at-bats
2012 postseason: HR every 41.4 at-bats
2011 regular season: HR every 36.4 at-bats
2011 postseason: HR every 26.9 at-bats
2010 regular season: HR every 35.8 at-bats
2010 postseason: HR every 36.4 at-bats
2009 regular season: HR every 32.9 at-bats
2009 postseason: HR every 32.2 at-bats
The bigger problem facing the Orioles: The Angels, Royals and Tigers were the three best teams in the AL at preventing home runs (in the case of the Angels and Royals, in part due to the parks they play in). For the Tigers, Max Scherzer, Justin Verlander and Rick Porcello each gave up 18 home runs in over 200 innings, not an excessive total. The most interesting matchup will be David Price, who allowed five home runs in his 11 starts with Detroit but 25 overall. He loves to pound the strike zone, but you wonder if he will look to expand it a bit against an Orioles team that doesn't draw many walks.
Remember, the Orioles reached the 2012 postseason with a similar type of offense -- that team hit 214 home runs and had a .311 OBP while this team hit 211 home runs with a .311 OBP -- and hit just .187 in a division series loss to the Yankees, hitting just three home runs and drawing only eight walks. Adam Jones went 2-for-23 in that series with six K's and zero walks, and he walked even less this season than two years ago.
Detroit Tigers: Defense
Yes, the bullpen is a potential liability; Mike Petriello outlined the problems with Joe Nathan & Co. the other day on ESPN Insider, although Anibal Sanchez could prove to be a viable weapon.
Aside from that, Detroit's defense is another issue. The Tigers ranked 28th in the majors in defensive runs saved at minus-65 runs. The biggest problem has been the lack of range of third baseman Nick Castellanos and the aging Torii Hunter in right field. Rajai Davis has also not graded out well in either left field or center field, despite his speed. He is actually a question mark for the division series due to a strained pelvic ligament suffered Saturday, although he is on the roster. If he can't go, Ezequiel Carrera is the likely starter in center.
Another possible issue if they end up meeting the Royals in the ALCS: The Tigers allowed the most stolen bases in the AL -- although they had the third-best caught stealing rate. Nathan is a huge liability here, allowing 10 steals, while none of the starters allowed more than 13.
Los Angeles Angels: Starting rotation
The Angels' finished sixth in the AL in rotation ERA -- ahead of the much-vaunted Detroit rotation -- but that includes the superlative season from Garrett Richards, who went down in late August with an ankle injury. Here's an interesting catch, however: The Angels had a 3.72 rotation ERA when Richards went down and 3.21 after. Much of that was due to the emergence of rookie Matt Shoemaker, who had a 1.13 ERA in six starts after Richards was injured. Shoemaker, however, missed the final two weeks of the regular season with a rib-cage injury. The Angels have him scheduled to start Game 2 of the series, with Jered Weaver and C.J. Wilson in Games 1 and 3.
The rotation is thin after those three. The Angels could bring back Weaver on three days' rest for Game 4, with Shoemaker going on regular rest in Game 5, so the division series setup with its two off days will help the Angels. Considering the depth of their bullpen, they won't expect the starters to go deep anyway. Still, with Shoemaker's health and Wilson's control as possible issues, the Angels may have to rely on their league-best offense to outscore their opponent.
Kansas City Royals: Lack of power
And you thought I was going to say Ned Yost! The Royals hit just 95 home runs, not only last in the American League but last in the majors. On the other hand, the Cardinals were 27th in the majors in 2013 (125 home runs) and reached the World Series and the Giants (103 home runs) were last in 2012 and won the World Series.
Still, for the Royals to win, they are going to have to hit some home runs or receive extraordinary pitching. The Cardinals hit six home runs in five games in beating the Pirates in last year's division series and then held the Dodgers to 13 runs in six games in the NLCS. But they hit just two home runs in the World Series and went down in six games. In 2012, the Giants hit 14 home runs in 16 playoff games (outhomering their opponents), so they picked up the pace.
Maybe the Royals can scratch and claw their way to enough offense, but they are not going to steal seven bases every game. To advance past the Angels, they are going to need a few big pops. Yost will presumably keep the same lineup he's used his past nine games, with Alcides Escobar, Norichika Aoki and Lorenzo Cain hitting 1-2-3. Those three combined for nine home runs all season. Meanwhile, his two leading home run hitters -- Alex Gordon and Salvador Perez -- have been batting sixth and seventh (and both struggled in September).