Half the teams in MLB are still in contention for the postseason, while some of those are already looking toward October. Which players deep on the rosters could make the difference in winning a championship? Here are 15 X-factors to watch down the stretch.
Position: Second in AL East, 3½ games out of first; lead second wild card by ½ game over the Rays
X-factor: Jason Hammel
Why not? The Orioles' 71-58 record still screams "fluke" -- they've been outscored by 46 runs and have the best record in one-run games (24-6) in baseball history -- but it doesn't matter now. They're five weeks from the promised land. To get there, they'll need Hammel to come back from the disabled list and stabilize a shaky starting rotation. Hammel was a surprise in April and May, his sinker/slider mix suddenly missing bats in the move from Colorado to the AL East and helping him to a career-best 3.54 ERA and 23 percent strikeout rate.
In July, Hammel was forced to the DL with cartilage problems in his right knee, underwent surgery, and is making a rehab start this weekend. For a team reliant on getting games to its bullpen, Hammel's return will be a significant help, but there remains some question as to whether he'll sustain his best-ever performance.
Chicago White Sox
Position: First in AL Central by 3 games over Tigers
X-factor: Alejandro de Aza
When everyone is healthy, a third of the White Sox lineup consists of players with sub-.300 OBPs. They've been able to survive that in part because minor league veteran De Aza has come out of nowhere to be their centerfielder and leadoff hitter, giving the top of the lineup some desperately-needed OBP. De Aza has been on the DL of late with bruised ribs, and while the Sox have survived -- 7-4 and 4.8 runs/game -- replacement DeWayne Wise's .306 OBP hasn't been a big part of that. The Sox need a healthy De Aza kicking things off to make their lineup function.
Position: Second in AL Central, 3 games behind White Sox; 2 games behind Orioles for second wild card
X-factor: Andy Dirks
Who? Dirks is a second-year player who has hit better at Triple-A and in the majors than he did at lower levels. He has been a godsend for a Tigers team crippled by Brennan Boesch and Delmon Young struggling mightily at prime hitting positions (rightfield and DH, respectively). Since returning from the DL (Achilles) August 3, Dirks has hit .338/.402/.481 and the Tigers are 12-7 when he starts. He is also a better defensive player than Boesch and Young are, helping a team whose defense is the worst in the game. The Tigers need Dirks to keep playing at a high level to fill out a lineup that is middle-heavy in more ways than one.
Los Angeles Angels
Position: Third in AL West, 9 games behind Rangers; 3 games behind for second wild card
X-factor: Garrett Richards
The Angels' bullpen has been a problem all season, one patched over briefly by Ernesto Frieri at the back end. Getting effective work from the aging plug-ins (LaTroy Hawkins, Jason Isringhausen, Scott Downs, Hisanori Takahashi) has been a struggle. Enter Richards, who was a starter until Zack Greinke arrived and a minor leaguer as recently as last week. Richards, recalled on August 23, has been used as a high-leverage reliever since his return, pitching the eighth inning of a tied game in Boston and closing a one-run game in Detroit, among other tough spots. He is a fastball/slider pitcher who works in the mid-90s and may be best suited as a reliever right now, even though the results -- five runs in 3 2/3 innings -- haven't been there. The Angels need someone to join Frieri and the occasionally-healthy Scott Downs in getting late-game outs. Maybe Richards can be the solution.
New York Yankees
Position: First in AL East by 3½ games over Orioles
X-factor: Andruw Jones
Injuries have hampered both the Yankees rotation and lineup, with superstars CC Sabathia and Alex Rodriguez spending lots of time on the DL, and first baseman Mark Teixeira now missing time as well. The latter two injuries have created a bit of a weakness against left-handed pitching, one exacerbated by the lack of production from the team's platoon leftfielder. With Rodriguez and Teixeira out, Jones has failed to bring the power and OBP from the right side, batting just .210/.281/.434 against southpaws after hitting .286/.384/.540 against them a year ago. With lefty starters prevalent on potential postseason opponents the Orioles, Rays and Rangers, Jones has to pull it together to give the Yankees much-needed offense from the right side.
Position: Second in AL West, 4½ games behind Rangers; lead AL wild card race by 1½ games over Orioles and 2 games over Rays
X-factor: George Kottaras
The A's offense is as Moneyball as it gets, relying on walks and homers to put runs on the board. The team thought they had a catcher in that vein in Derek Norris -- part of the haul in dealing away Gio Gonzalez to Washington -- but after a big start, Norris is down to .197/.272/.347. With incumbent Kurt Suzuki having also been shipped to D.C. in a separate deal to make room for Norris, it may be up to former Brewer Kottaras to provide some offense. Kottaras had a .409 OBP for the Brewers before coming over, but has hit just .154/.241/.269 with the A's, while allowing all nine basestealers to succeed. One of these two players will have to come around to fill what has been a black hole for Oakland all year long; Kottaras, a veteran lefty batter with a good approach at the plate, is the better option to do so.
Tampa Bay Rays
Position: Third in AL East, 4 games out of first; ½ game out of second wild card
X-factor: Ryan Roberts
After years of putting his best defensive lineups on the field, Joe Maddon gave up in August, shifting Ben Zobrist to shortstop and Ryan Roberts to second base. It's not a bad tradeoff for a team that has struck out a league-leading 1,076 men, more than 22 percent of the batters who have come to the plate. While Zobrist has been a good defender at second base and a good hitter everywhere, this plan rises and falls on Roberts, who is less nimble at the keystone and who hasn't hit at all -- .212/.300/.317 -- since coming over from the Diamondbacks in July. The Rays, 10-6 with a Zobrist/Roberts double-play combination, need Roberts to get back to his lefty-smashing, power-hitting ways for this plan to work.
Position: First in AL West, 4½ games ahead of Athletics
X-factor: Mitch Moreland
The Rangers are the best team in the AL and about a 98 percent favorite to make the postseason, so this is about the playoffs. Last season, Moreland's struggles at the plate exacerbated the Rangers' left/right imbalance, making the team susceptible to both good righthanded starters and, more critically in the World Series, nasty power righties out of the bullpen. Moreland, having the best season of his career (.296/.342/.530), will be a great solution to that problem, as if he's hitting well he can be positioned higher in the lineup to break up the Rangers' righty bats. Caveat: Moreland has a poor 43/14 K/UIBB against right-handers, so there's no guarantee he can keep hitting at this level. He, David Murphy and Josh Hamilton are the entire Rangers' team from the left side, so he's critical to their World Series chances.
Position: Second in NL East, 5 games behind Nationals; lead NL wild card race by 2½ games over Cardinals and 3½ games over Pirates
X-factor: Andrelton Simmons
The Braves' one lineup weakness is shortstop, where prospect Travis Pastornicky disappointed both to start the year and in a second trial in the summer. The team traded for glove man Paul Janish, who has been spectacular defensively but desperate (.197/.267/.245) with the bat. The return of Simmons, who broke his right pinky on July 8, is highly anticipated. Simmons is already one of the best defensive shortstops in the game, and his bat had been a pleasant surprise: .296/.336/.452 in 33 games. Getting Simmons back will bolster the offense and even provide a boost defensively over the excellent Janish.
Position: First in NL Central, 8 games ahead of Cardinals
X-factor: Drew Stubbs
After last year, we know to never say never, but the Reds are as safe a bet to set their playoff rotation as anyone. That doesn't mean they're perfect, however. They are once again struggling at the top of the lineup, with a wretched .248 OBP from the leadoff spot and a poor. 314 OBP from the second slot. Joey Votto's return will be more useful if Votto will get to bet with runners on base now and again. It's time for Stubbs, a superior defensive center fielder with great tools to play better. Stubbs has gone backwards in his age-27 season, setting career lows in everything and barely being a replacement-level player. The Reds are committed to him, and for his reputation as a manager who doesn't work well with young players, Dusty Baker has been exceptionally patient with Stubbs. Stubbs has to return that faith by becoming an asset -- a .340 OBP from here on out will be fine -- near the top of the lineup.
Los Angeles Dodgers
Position: Second in NL West, 3½ games behind Giants; 1½ games behind Cardinals for second wild card
X-factor: Chad Billingsley
Clayton Kershaw is the ace every postseason team wants to have, but behind him, the Dodgers' rotation is largely a bunch of innings guys -- yes, including Josh Beckett. Billingsley is better than that, which is why his inability to stay in the rotation this season has to be frustrating for Los Angeles. Between DL stints -- both times for pain in his pitching elbow -- Billingsley started seven games with a 1.80 ERA and a 28/11 K/BB. The Dodgers won all seven games he started. If he's done for the season -- and he may well be -- there's a huge hole in the rotation behind Kershaw. What the Dodgers can get from Billingsley, who left his most recent start on Aug. 24 early with a sore elbow and hasn't pitched since, from here on out will go a long way toward determining their fate.
Position: Third in NL Central, 9 games behind Reds; 1 game behind Cardinals for second wild card
X-factor: Jason Grilli
The Pirates' bullpen hasn't been quite as effective as Baltimore's bullpen has, but it's played a similar role in their success with just as anonymous a cast. Perhaps the best story has been Grilli, a top-five draft pick 15 years ago who, at 35, has become the most surprising shutdown reliever in the game. Grilli, who missed all of 2010 after suffering a knee injury in spring training, has bounced back to strike out an amazing 38 percent of the batters he's faced this season, with five strikeouts for every walk allowed. The Pirates have to win the close games, and having Grilli pitching the eighth inning has made them more likely to do so. With his role now critical, the Pirates need him to keep pitching as well as he has if they're to make the postseason for the first time in 20 years.
St. Louis Cardinals
Position: Second in NL Central, 8 games behind Reds; lead second wild card by 1 game over Pirates
X-factor: Jaime Garcia
With Adam Wainwright returning to his pre-surgery form, the Cardinals seem to have their No. 1 starter for the postseason. Their No. 2 is in question, for as well as both Kyle Lohse and Jake Westbrook have pitched, their pitch-to-contact style doesn't always play well against playoff lineups. Missing bats matters.
That's where Garcia, just off the DL after missing much of the season with a sore left shoulder, comes in. In two starts since coming off the DL, Garcia has 15 strikeouts and just two walks allowed. Garcia is more of a power pitcher than the other two and, at his best, is the clear No. 2 in a postseason rotation. His being a southpaw could be important as well, as the lefty-heavy Reds loom as a possible October opponent.
San Francisco Giants
Position: First in NL West, 3 ½ games ahead of Dodgers
X-factor: Brandon Belt
While the Dodgers have been acquiring every high-priced big name this side of George Clooney, the Giants have suffered the loss of their best hitter in Melky Cabrera and the disastrous month of their big trade pickup, Hunter Pence. Throw in Pablo Sandoval coming back off the DL without his bat, and the Giants' offense is sagging heading into September. That's why Belt is important.
Perceived as a disappointment for his lack of power -- four homers and a .390 SLG -- Belt is one of the Giants' most reliable sources of OBP, with a .356 mark despite inconsistent playing time. The Giants need all the baserunners they can get in a post-Melky world. Where Belt can really contribute, though, is by finding his power stroke. The fact is, low-SLG first basemen aren't helpful. Belt doesn't have to hit the longball -- a challenge for any lefty batter at AT&T Park -- but he does need to drive the ball more for extra-base hits of any kind, making up for the lost SLG that Cabrera took with him when he was suspended.
Position: First in NL East, five games ahead of Braves
X-factor: Ross Detwiler
The Nationals are the NL's Rangers, an overwhelming favorite to get into the tournament, so this is about what happens after they get there. As unfair as it is to Detwiler, he's not going to be evaluated as the effective lefty he is come October. No, he's going to be "the guy who isn't Stephen Strasburg" every time he takes the mound. The Nats' plan to shut down Strasburg means that Detwiler, their No. 5 starter, will be elevated to the postseason rotation. Himself a former first round pick, Detwiler has overcome health issues to establish himself this year, with a 3.32 ERA and an 83/36 K/BB. He's a good pitcher -- but he's not Stephen Strasburg. The Nationals will be putting a lot of pressure on him come the Division Series.