This is the time of year when seasons are made and broken. A Cy Young Award challenger can fall out of the race with one disastrous outing. Similarly, a string of good performances can catapult someone back into the running.
The same goes for the teams. With the new second wild card this year, the races are much closer. Nine teams are within 3.5 games of a playoff berth. We take a look at the players who should turn it on down the stretch.
Had the season ended in May, Josh Hamilton would have been the unanimous AL MVP after perhaps the greatest year in major league history.
He was on course for more than 90 home runs for over two months and while he's slowed down since then, he still leads the majors with 39 long balls and 116 RBI.
If the Texas Rangers are to win a third consecutive American League pennant, it will be on the back of their star outfielder.
Derek Jeter will be in the Hall of Fame. His No. 2 will be retired by the club. He will be forever adored in New York as one of their greatest-ever players. But he's not finished yet.
After back-to-back poor seasons, Jeter has rebounded in 2012. He leads the major leagues in hits with 183 and has 14 home runs and a .318 batting average, both his best since 2009.
The New York Yankees have a good case for having the best second baseman in all of baseball. Robinson Cano has been a revelation for the Bombers, batting at least .300 with 25 home runs and 40 doubles in each of the last four seasons. In a season which has seen the Yanks struggle with injuries to countless key players, Cano has been a consistent strong presence in the lineup.
It would just be the perfect storybook finish to a miserable Boston Red Sox season, wouldn't it?
The last time the Sox traded a $20 million slugger to the Los Angeles Dodgers midseason, four years ago, it was Manny Ramirez who was shipped to the West coast. He went on to bat almost .400 down the stretch and take the Dodgers to the NLCS.
Adrian Gonzalez, who was traded as part of a nine-player waiver deal involving more than a quarter of a billion dollars in salary commitments, has not lit the world alight in his first 12 games with LA, but he is too good a hitter to finish with a mere .260 average.
Andrew McCutchen has made a decent push for the NL MVP, just as his Pirates have made a surprising challenge for the postseason. If the Bucs are going to make the playoffs for the first time in almost two decades, only McCutchen can step up to take them there.
Mike Trout might not win the AL MVP in his rookie season, a feat which has only been accomplished twice. Indeed, he might not have a good September and see his spectacular numbers come back down to Earth slightly.
The Angels' phenom has taken his foot off the gas of late. A .284 average in August was the worst monthly total he's posted this season. September hasn't started well, either, as he's gone 5-for-22 with no extra base hits. However, a glorious run of form down the stretch would give him the greatest rookie season in the league's history.
Joey Votto is the future for the Cincinnati Reds. The 2010 NL MVP is signed through 2013 on a $263 million contract. He spent almost two months on the DL this season but was 2-for-3 in his first game back on Wednesday.
In his career, Votto has posted his highest slugging percentage in the months of September and October, at .591.
The Chicago White Sox have had a surprising 2012 and have made life in the AL Central more difficult for the Detroit Tigers than expected. It took the Tigers, who were six games back in mid-June, a while to get going. Now, though, they are just one game behind the Sox for the division lead.
If they are to repeat the successes of 2011, which saw them take their first division title in 24 years, they will need their ace to dominate down the stretch. Reigning MVP and Cy Young awards winner Justin Verlander pitched to a 2.55 ERA last September. His first of the month this year was similarly dominant, allowing one run in eight innings against the White Sox.
The Washington Nationals have undone 44 years' worth of disappointment this season, turning a franchise which had not had a winning season since 2003 into arguably the best team in baseball. The last few years have seen the Nats bring in a host of new players including Gio Gonzalez from the Oakland Athletics, who is tied for the major league lead in wins.
Gonzalez is 18-7 with a 2.98 ERA. He is averaging more than a strikeout per inning and has three times as many whiffs as walks.
He's also pitching his best at the right time. Gonzalez has not allowed a run in his last 16 innings, surrendering just eight hits and three walks with 17 strikeouts in that span.
The San Francisco Giants' rotation has been very good this season, despite a Tim Lincecum collapse no one could have foreseen. Matt Cain has been the highlight, with a 13-5 record, sub-3.00 ERA, 170 strikeouts, a one-hitter and a perfect game. He has never had a dominant September, but with the Giants only leading the NL West by 4.5 games, this is the perfect year to start.