The last four weeks of the 2013 MLB regular season are upon us as the season enters its final month.
The playoff races are heating up in both leagues, and they will likely come down to the wire.
With so many teams being so close, any one player could potentially decide his team's playoff fate during the final month of the season.
Here are a few guys who are the most likely candidates to impact a playoff race.
After Nelson Cruz was suspended 50 games for his involvement in the Biogenesis scandal, the Texas Rangers needed someone to step up and fill the void left by their star right fielder.
The team decided to look for replacement options outside of its organization, and trading for Alex Rios was the answer.
It's not easy replacing Cruz, who had 27 home runs and 76 RBIs in 108 games before he was suspended. However, Rios has answered the call, batting 26-for-89 with five doubles, a triple and two home runs. He has also generated 22 runs (counting runs scored and RBI) in 22 games.
Since Cruz was suspended the Rangers have gone 19-8, thanks in large part to Rios and the offense.
As the Rangers look to win a close divisional race in the AL West against the Oakland Athletics, it will be important that Rios continues to generate runs.
The Oakland Athletics are one of the best teams in MLB, albeit one of the least sexy in terms of stars.
One of the few true superstars on the team is Yoenis Cespedes, and the weight of the team's playoff hopes will rest on his shoulders.
Cespedes showed off his tremendous power in July when he won the Home Run Derby, but he's cooled off since. He has only six home runs in the second half of the season and just one since Aug. 17.
Cespedes will be asked to lead an offense that is backing up one of the top pitching staffs in the league. The Athletics have pitched their way into their current position, but now they'll need all the offense they can get.
However, if he can't break out of his power slump, the team is in trouble.
Jason Grilli was once the best closer in baseball, but his fairy tale hit a bump in the road when he was placed on the DL.
Grilli was activated Tuesday, but it remains to be seen how effective he'll be down the stretch.
The Pittsburgh Pirates aren't trying to push their 36-year-old reliever, who was a closer for the first time in his career earlier this season. After not pitching for roughly six weeks, Grilli will be eased back into his role, as Mike Axisa of CBS Sports reported that he may not be closing right away.
Grilli was 30-for-31 in save opportunities before he hit the DL. His 2.34 ERA and 0.92 WHIP were both career bests, and he was enjoying the most successful season of his life.
Grilli's return will be crucial for the Bucs as they bring back a pitcher with experience closing games. However, his performance after this lengthy absence could go either way, and whether the team wins the NL Central could come down to Grilli.
The Tampa Bay Rays once looked like a lock for the postseason, but a 1-8 stretch at the end of August into September has set them back a ways.
Sitting just 2.5 games up on the New York Yankees (yeah, they're still around) for the final wild-card spot in the AL, the team is in danger of falling out of the playoff picture.
The Rays have run into some offensive trouble as of late, scoring just 2.1 runs per game during their 1-8 stretch. The team wasn't scoring enough to win games, and one of the biggest culprits for the slump was rookie sensation Wil Myers.
After batting .340 with eight home runs through Aug. 9, Myers has gone cold. He is now batting .286, and he went just 2-for-27 without a single RBI during the team's 1-8 stretch.
Myers was once the best offensive weapon on this team, but as he's fallen into a slump, so has the team. His importance can't be overstated, and even as a rookie, he will be the deciding factor as to whether the Rays are still playing in October.
Despite ranking fourth in MLB in runs scored, the Baltimore Orioles are on the outside looking in when it comes to the AL playoff picture.
Sitting three games behind the Tampa Bay Rays for the second wild-card spot, the team needs its pitchers to step up and help the offense in the final month of the season.
The team's pitchers have struggled all year, ranking 26th in ERA. That's pretty bad, but things get even worse when you just look at the team's starting rotation, which doesn't have a single pitcher with an ERA better than 3.71.
With such terrible pitching, it's hard to imagine that the Orioles have even done as well as they have. Without the team's starting rotation turning it on for the final month of the season, the O's will miss out on the postseason.
Josh Reddick broke out for the Oakland Athletics last season, blasting 32 home runs in 157 games. He averaged fewer than five games between home runs and was key to the team's success.
However, Reddick has struggled this year. If he kept up his pace from last year he should have roughly 20 home runs right now, but he's sitting at just 10.
Reddick is currently on the DL, but Susan Slusser of the San Francisco Chronicle tweeted that he feels good and is hoping to return as soon as possible.
After seeing Coco Crisp get a cortisone shot and come back on a hot streak, the Athletics are hoping Reddick can do the same. He could be a key piece for the team down the stretch, as he has the potential to be a vital offensive weapon. And the team is in desperate need of a player like him if it is going to pass the Texas Rangers.
The Cincinnati Reds have one of the best teams in the MLB. With the third-best offense and a solid starting rotation and back-end of the bullpen, Cincy has the potential to make some noise in October.
But first, they have to get there.
The team is looking to pass both the Pittsburgh Pirates and St. Louis Cardinals in the NL Central to avoid playing in the Wild Card Round, but it will need another pitcher to do so; a versatile arm that can help in both the bullpen and the starting rotation.
Enter Tony Cingrani. Posting a sub-3.00 ERA this year as both a starter and reliever, Cingrani has been a key piece for the team.
If the Reds are going make a run at the NL Central, they will need Cingrani to pitch as well as he did before he went on the DL on Aug. 25.
B.J. Upton is arguably the second-biggest bust of the 2012 MLB free-agent class—behind Josh Hamilton.
After signing a five-year, $75.25 million contract, Upton is batting a hair under the Mendoza line and has just nine home runs. He has been putting up mediocre numbers at best and certainly hasn't lived up to his contract.
Atlanta Braves fans certainly believe the less said about Upton the better, but he can turn things around in September.
If Upton is able to turn it on and help the Braves clinch home-field advantage, then the first five months of Upton's season will be forgiven.
The Braves need an extra push if they're going to stay ahead of the Los Angeles Dodgers in the NL, and Upton could provide the force if he starts playing like his old self.
Clay Buchholz hasn't pitched since June 8, but before he hit the DL he was 9-0 with an ERA of 1.71 and looked like the Cy Young favorite.
After having his final rehab start on Thursday, Buchholz will soon be ready to return to the Boston Red Sox as the team looks to lock up the No. 1 playoff spot in the AL.
The Red Sox have the second-best offense in baseball, trailing only the Detroit Tigers in runs scored.
Buchholz is the team's ace, and without him the starting rotation hasn't been as effective. His return will be key, both in September and October.
If Buchholz comes back at 100 percent, he could ensure that the Red Sox stay ahead of the Tigers for the top seed in the AL and perhaps help the team win another World Series.
Yasiel Puig is arguably the most gifted player in MLB, but he is arguably the most boneheaded.
For every great play Puig makes, there's another play he makes that leaves everyone scratching their heads. He's just as likely to lose the Los Angeles Dodgers a game as he is to win them one, which is what makes him so important.
Puig is always an X-factor when he plays, and these next four weeks will be very telling.
The Dodgers are looking to clinch home-field advantage by passing the Braves, but at a point when every game matters, Puig's consistency will be key.