If they fall out of contention, teams like the New York Mets or Los Angeles Angels will look to deal their star players to alleviate their financial burden and rebuild for the future.
Carlos Beltran has revitalized his career this year, hitting for both average and power. But at the age of 34, he doesn't have many productive years left. New York will want to deal him in order to improve its farm system as it enters a rebuilding phase.
Jered Weaver is on track to break all sorts of arbitration records in the coming offseason, and the Angels would be thrilled to get him and Scott Boras out of their lives if they can deal Weaver for some promising prospects.
Here are the top seven potential deadline deals.
Maggio Ordoñez does not have much of a role anymore on the Detroit Tigers.
The aging slugger is becoming a liability defensively but cannot be put at the DH spot, where he would take at-bats away from Victor Martinez or Alex Avila.
The New York Yankees have primarily had Jorge Posada playing DH, but the old Yankee has only hit .226/.321/.375 in his 51 games this year.
Ordoñez, hitting only .168, might not be much of an improvement. But a move out of the outfield could help his numbers.
Besides his inconsistency at the plate, the $5.8 million remaining on his contract is the largest deterrent for potentially interested teams. But $5.8 million is nothing to the Yankees, who will go out and get Ordoñez if they think he will help them catch the Red Sox and their offensive juggernaut.
The recent call-up of highly touted prospect Mike Moustakas has left Wilson Betemit without a starting job.
Betemit should draw interest from every team in need of help at third base. He has put up a .289/.348/.411 line so far this year for a salary of just $1 million.
Ultimately, the Seattle Mariners would be a great fit for Betemit. Seattle has suffered through two months of Chone Figgins and his sub-.200 average and would jump on the opportunity for a cheap replacement.
Seattle is a game over .500 and just two games behind the Rangers. It will be highly motivated to improve its team for a shot at the playoffs.
A popular preseason pick to win the AL West, the Oakland A's are currently sitting in the cellar at nine games under .500.
Their pitching has been stellar as expected, but their ragtag offense just hasn't put it together this year.
Any starter on the A's team could be on the move, including Josh Willingham, David DeJesus and Mark Ellis.
Coco Crisp likely commands the most value as a good defensive center fielder with leadoff potential.
Though he's hitting just .258 so far this year, Crisp is a .276 career hitter with a 77 percent success rate on the basepaths. Just last year, Crisp was 32-of-35 on steal tries.
The Braves opened the year with Nate McLouth, currently on the DL, as their everyday center fielder.
Atlanta might not want him back, as he was hitting .238/.332/.341 before his injury.
The speedy Crisp would provide an upgrade in the outfield for Atlanta, which ranks last in the major leagues with only 19 steals as a team.
For the first time this millennium, the Pittsburgh Pirates could be buyers at the deadline.
At 32-33, Pittsburgh is one game under .500 and five games out of first. It will certainly be excited to prowl the market for the one or two missing pieces it needs.
First baseman Lyle Overbay is having a disappointing season, hitting just .236/.305/.369 with five homers.
Carlos Peña probably wouldn't hit for much more average, but he does already have nine dingers on the year.
It should also be noted that Peña has hit .250/.388/.492 since May first, a huge improvement over the .159/.289/.175 eyesore he posted in April.
The New York Mets still have to decide whether they even want to trade Reyes this season.
They might just want to hang on to the star shortstop and take a chance at re-signing him this offseason, accepting the compensation picks if he slips away.
If the Mets do decide to trade Reyes, the St. Louis Cardinals are an intriguing candidate.
Current shortstop and leadoff hitter Ryan Theriot has played well for the Cardinals this year, hitting .291/.339/.354, but he has only four stolen bases.
Jose Reyes would provide an improvement over Theriot, whose defense at short is shaky at best. Acquiring Reyes would move Theriot back to second base, where he played most of 2010, and put Skip Schumaker and his .236 average on the bench.
St. Louis would not be interested in signing Reyes to a long-term deal, as it will be saving every penny for Albert Pujols. But Reyes could be an exciting rental to propel the Cardinals deep into the playoffs in 2011.
Jered Weaver and Scott Boras are angling to get Weaver the highest arbitration deal of all time this upcoming offseason.
The Angels are in third place and 4.5 games out of first. If the Halos slip even further in the standings during the 12-game road trip they begin this week, they could easily become sellers at the deadline.
After leading the league in strikeouts in 2010, Weaver has had a fantastic start to his 2011 campaign. He is 7-4 with a 2.24 ERA and an impressive 0.95 WHIP.
The New York Yankees have enjoyed considerably more success from their starting pitchers than anybody reasonably expected. Freddy Garcia and big Bartolo Colon have ERAs under four, and A.J. Burnett and Ivan Nova are just over at 4.09 and 4.30 respectively.
But Colon has hit the DL, and Burnett has regressed, notching a 5.06 ERA in his past six starts. The Yankees will need pitching help, and a legitimate ace like Weaver would be the ultimate prize.
The AL East rival Red Sox also lack depth at starting pitcher and will likely also make an offer for Weaver should he become available. The Red Sox's involvement would spark quite the bidding war, which would only be beneficial for the Angels.
Because of recent news that the New York Mets will take their chances on re-signing Jose Reyes, Carlos Beltran has become the most likely player out the door.
Beltran has improved his stock dramatically in 2011, hitting .282/.365/.498 with nine homers and a league-high 20 doubles.
Milwaukee has featured a platoon of Carlos Gomez and Nyjer Morgan in center, who are hitting a combined .246/.306/.397, a figure that must go up for Milwaukee to contend this year.
The Mets have offered to pitch in for part of Beltran's salary if they can get some prospects in return, which would give Milwaukee the choice between completely depleting its farm or ponying up the extra dough to complete the deal.
Because of Milwaukee's current lack of prospects, this deal may fall through. But it would be a great fit for the Brew Crew and would line up nicely with Beltran's request that he get traded to a team in contention.