The playoff picture is coming into focus, with four of the six divisions locked up and a quartet of wild-card contenders -- the Yankees, Royals and Orioles in the American League and the Nationals in the National League -- barely hanging on.
Entering this final week of the regular season, there are 11 remaining teams that have obviously distinguished themselves over the course of the season's first 25 weeks. Ten of them are in playoff position with the Rangers, who are 1 ½ games out in the AL wild-card race, the only team on the outside looking in that is not on life support. Still, there's a very real chance no club reaches 100 wins. That absence of a superteam means there will be plenty of parity in the postseason field. Each team listed below has a legitimate chance of winning the World Series -- and each has a weakness that could trip it up in October. Herewith are the Achilles' Heels for the contending teams.
Boston Red Sox: Team defense
The Red Sox have allowed more runs than any likely AL playoff team except for the Indians, and their team defense could be especially problematic if centerfielder Jacoby Ellsbury doesn't return from his foot fracture and if rightfielder Shane Victorino has any more difficulty with either his jammed thumb or sore left hamstring. Ellsbury ranks fourth among centerfielders with 14 runs saved, according to the Fielding Bible, and Victorino ranks second among rightfielders with 23 runs saved.
Those two -- along with Dustin Pedroia, the top-ranked defensive second baseman -- are the brightest spots in a fielding crew that otherwise ranks 24th in the majors in park-adjusted defensive efficiency, according to Baseball Prospectus. Also, after trading Jose Iglesias to Detroit, Boston has only the below-average Stephen Drew at shortstop.
Cleveland Indians: Competing with the best
Much has been made about Cleveland's soft end-of-season schedule, in which the club has feasted on AL bottom-feeders to propel itself into contention, but that has actually been the story all year. The Indians have the majors' best record against opponents with losing records at 50-18 (.735) but are just 36-52 (.409) against teams with winning records, the worst mark among contenders by nearly 60 points of winning percentage.
Among possible playoff opponents, Cleveland has winning records against only the AL West teams -- 5-2 vs. Oakland and 5-1 vs. Texas -- but is a poor 4-15 against Detroit, 1-6 against Boston and 2-4 against Tampa Bay. As it lines up now, the Indians would have to face Tampa Bay in the wild-card game and, should they advance, Boston in the ALDS.
Detroit Tigers: Bullpen
The 'pen was Detroit's biggest problem in last year's pennant-winning season, too, and somehow it got worse this season. In 2012 the Tigers had a 3.73 regular season bullpen ERA that ranked a middle-of-the-pack 16th in the majors; in '13 the unit's ERA has regressed to 4.07, which ranks just 25th.
Oakland A's: Serving up home runs
The A's have baseball's most flyball-prone staff -- 49 percent of batted balls, three percent more than any other club -- which has worked fine during the regular season, given the club's spacious home ballpark and terrific outfield play, but could be problematic in the postseason. When every club is throwing its best starters and more liberally matching up its best relievers, runs can be harder to come by in October, meaning playoff home runs are especially meaningful. Also, Oakland may not get homefield advantage and could have to play a majority of games in a series at smaller stadiums like Boston's Fenway Park.
Tampa Bay Rays: Road play
For all the knocks that Tropicana Field takes for having turf, a dome, poor aesthetics and worse attendance, the Rays have made it into a nice homefield advantage with a 49-30 (.625) record there, compared to just a 37-40 (.480) mark away from home -- that's the worst road record among the strongest playoff contenders in either league. The pitching staff particularly minds leaving the confines of the offense-suppressing Trop, as its ERA jumps from 3.48 at home to 4.09 on the road. The Rays are 12-2 when Matt Moore starts on the road but only 25-38 when anyone else does.
Texas Rangers: September play
There's a limit to how important momentum is, but it's hard to rebound from the disastrous September the Rangers have had. They are 5-15 this month and in serious danger of not even making the postseason. The offense recently had a seven-game homerless drought and is averaging only 3.4 runs per game, which ranks 27th in the majors; the rotation has a 4.57 ERA, which ranks 23rd.
Atlanta Braves: Waning offense
Since the Braves reeled off 16 straight wins in late July and early August, the offense hasn't been the same. That winning streak ended on Aug. 10, and from that day forward -- a span of 39 games in which Atlanta has gone 21-18 -- the lineup has had just a .667 OPS that ranks 26th in the majors during that span and a .230 average that ranks 28th. While Freddie Freeman has been scorching hot over these past six weeks, posting a .971 OPS, Justin Upton, Evan Gattis, Brian McCann, Dan Uggla, Jordan Schafer and B.J. Upton all have an OPS that's below .700.
Cincinnati Reds: Top-heavy lineup
The Reds have an especially unbalanced lineup. Their three most productive hitters this season, by far, have been Joey Votto, Shin-Soo Choo and Jay Bruce, who have posted OPS' of .934, .884 and .820, respectively, whereas no other regular on the club has a mark higher than .720. If any of those three hitters falls into a slump, Cincinnati could have trouble scoring runs. It also just so happens that those three hitters are all lefthanded, and while Votto still hits lefties very well (.843 OPS) Bruce is just decent (.752 OPS) against southpaws and Choo really struggles (.572 OPS).
Los Angeles Dodgers: Injury issues
Since the Dodgers got hot on June 22, they have gone 60-24, amazingly sustaining a .714 winning percentage for more than half a season. (For perspective's sake, playing .714 ball for 162 games equates to 116 wins.) It's hard to say that Los Angeles has had much of a weakness in the second half, though it has twice lost four straight games in the past fortnight.
The most glaring vulnerability has been the health of stars Hanley Ramirez, Matt Kemp and Andre Ethier. Ramirez has recently struggled with an irritated nerve in his back and has made two DL trips; Kemp, meanwhile, has logged three DL stints though he has returned to play in the Dodgers' last seven games; Ethier, plagued by shin splints, has had just one plate appearance since Sept. 13.
Pittsburgh Pirates: Hitting with RISP
The Pirates have really struggled to hit with runners in scoring position all season. They have just a .656 OPS in those situations (compared to a major league average of .725), which ranks 27th in the majors and would be the worst of any playoff team since 1983. The addition of Marlon Byrd has helped, but the lineup is still sub-par at driving home runners from second or third. The league average for scoring a runner from third with fewer than two outs is 50 percent, yet Pittsburgh has driven home just 42 percent of runners in those situations
St. Louis Cardinals: Hitting lefthanded pitching
Despite an impressive roster of righthanded and switch hitters -- Allen Craig, Matt Holliday, Carlos Beltran, Yadier Molina and David Freese -- St. Louis has struggled all year against lefthanded pitching. The Cardinals are just 17-23 (.425) in games when their opponent starts a southpaw on the mound, as opposed to 74-42 (.638) against righties. They have a .669 OPS against lefties, which ranks 27th in the majors and could be problematic against NL playoff teams with multiple lefty starters: the Braves have Mike Minor, Paul Maholm and Alex Wood; the Dodgers have Clayton Kershaw, Hyun-jin Ryu and potentially Chris Capuano; and the Pirates have Francisco Liriano and Jeff Locke.