The week ahead, however, will give several contenders a chance to burnish their road records, as teams like the Marlins, Yankees, Dodgers, Twins and Red Sox begin road trips of a week or longer. Of those five, only the Yankees (25-24) are above .500 on the road.
American League East division leader Tampa Bay, 23-28 on the road, faces Cleveland for three at the Trop in a series that begins Monday, before the Rays head west on a 10-game trip to Seattle, Oakland and Texas.
New AL Central leader Minnesota heads west to Seattle for three and then to Kansas City for three against the Royals.
Newest Dodger Manny Ramirez hits the road as Los Angeles travels to St. Louis and San Francisco.
Meanwhile, the White Sox play their first home game since July 23 on Tuesday against Detroit, which will also be the home debut of Chicago's new center fielder, Ken Griffey Jr.
Two other division leaders, the Cubs and Angels, are at home this week. The National League Central-leading Cubs host Houston for three followed by a series against St. Louis.
Finally, about 10 teams are expected to have representatives on the road Tuesday, when free agent right-hander Freddy Garcia throws for scouts in Miami.
Here's the lineup:
Yankees at Rangers, Monday-Thursday: A key stretch of the season begins today for the Yankees, who will play 39 of their remaining 51 games against teams at or above .500. Starting with the opener of a four-game series against the Rangers, the Yankees will play 16 of their next 19 games on the road.
The series is of added importance for both teams. The Rangers, who are in fourth place in the Wild Card standings, 6 1/2 games behind Boston, have more home games the rest of the way than any team in the Majors. Texas leads the Majors in runs scored, and the club has a winning record at home.
The Yankees will go with Joba Chamberlain (4-3, 2.24 ERA) against Vicente Padilla (12-5, 4.52) on Monday, with left-hander Andy Pettitte (12-8, 4.18) matched up with Texas lefty Matt Harrison (2-2, 7.40) on Tuesday. It will be former Ranger Sidney Ponson (6-2, 4.23) against Rangers right-hander Tommy Hunter (0-0, 10.80) on Wednesday, and a pair of right-handers, Mike Mussina (14-7, 3.44) and Scott Feldman (4-4, 4.97), on Thursday.
Astros at Cubs, Monday-Wednesday: The Astros are 13 games back in the NL Central race, but don't tell them they're out of it. They have won seven of their past nine games and are 11-6 in their past 17 games. The Astros have won five of their past six series, including one in which they took two of three from the Cubs at Minute Maid Park.
Now comes the litmus test. If the Astros, eight back in the Wild Card standings, can win a series at Wrigley Field, it will give their flickering postseason hopes a boost. The Cubs have the best home record in the Major Leagues (41-15).
The probables: Astros right-hander Brian Moehler (6-4, 4.23) vs. Cubs right-hander Ryan Dempster (12-4, 2.90) on Monday night, Astros lefty Wandy Rodriguez (6-4, 3.61) vs. Rich Harden (1-1, 1.11) on Tuesday afternoon and Astros right-hander Brandon Backe (6-10, 4.72) vs. Jason Marquis (6-7, 4.68) on Wednesday.
Tigers at White Sox, Tuesday-Thursday: Swept by Tampa Bay over the weekend, the Tigers will try to regroup against a Chicago team that fell out of first place Sunday for the first time since May 17. The White Sox, after a 4-6 road trip, are back at U.S. Cellular Field to face Detroit for three, followed by three against the Red Sox.
The Tigers will go with lefty Nate Robertson (6-8, 6.06) against Gavin Floyd (11-6, 3.43) in the opener. Wednesday's game will pit Detroit right-hander Justin Verlander (8-11, 4.49) against lefty John Danks (8-4, 3.31). On Thursday, it will be right-hander Zach Miner (5-4, 3.77) against Chicago's Javier Vazquez (8-9, 4.66).
Dodgers at Cardinals, Tuesday-Thursday: These two teams aren't getting as much attention as some of the front-runners, but both are very much in the thick of things and both have strengthened themselves for the stretch run -- the Dodgers with the addition of Manny Ramirez and the Cardinals with Chris Carpenter.
Carpenter (0-0, 2.25) will start Tuesday against Chad Billingsley (11-9, 3.05). Wednesday will match Joel Pineiro (3-5, 5.04) against Derek Lowe (8-9, 3.70). Kyle Lohse (13-3, 3.73) will go against Clayton Kershaw (1-3, 4.02) on Thursday.
Marlins at Phillies, Tuesday-Thursday: The biggest week of the season to date for Florida, as the NL East contenders go on the road for series against the first-place Phillies and the third-place Mets. The Marlins lead the NL with 33 come-from-behind wins.
Josh Johnson (1-0, 4.18) will start opposite Philadelphia's Jamie Moyer (10-6, 3.79) on Tuesday. The Marlins will go with right-hander Anibal Sanchez (1-0, 3.18) on Wednesday against Phillies right-hander Kyle Kendrick (9-5, 4.59). Thursday's finale will match Florida's Chris Volstad (2-2, 3.25) against Philadelphia left-hander Cole Hamels (9-7, 3.37).
Red Sox at White Sox, Friday-Sunday: Boston and Chicago, both in second place in their respective divisions and two teams that made headlines on Trade Deadline day with acquisitions of Jason Bay and Ken Griffey Jr., respectively, meet for three games at the Cell in a series that could have postseason implications.
Marlins at Mets, Friday-Sunday: The Marlins took two of three from New York in Miami last week before splitting four with Colorado. After leaving Florida, the Mets were swept at Houston over the weekend.
Now the Mets are back home for a seven-game homestand -- three with San Diego and three with the Marlins, followed by a makeup game against Pittsburgh on Aug. 11.
The Florida series is particularly important, not only because it is against a key rival in the division race, but because the Marlins are the only team with a winning record that the Mets will face over their next 21 games.
After this stretch, the schedule turns much tougher for the Mets, who will go on the road for series at Philadelphia, Florida and Milwaukee before returning home on Sept. 5 to face the Phillies.
Yankees at Angels, Friday-Sunday: The Yankees and Halos split a four-game set at Yankee Stadium over the weekend, and now they'll hook up again in Anaheim for three more.
Cardinals at Cubs, Friday-Sunday: Another showdown series for the Cubs. The Cardinals are hanging tough, and now they've got Carpenter back to help in their bid to catch the Cubs and NL Wild Card leader Milwaukee.
The probables are subject to change but, if both teams stay on rotation, it should be Ted Lilly vs. Kyle Lohse on Friday, Carlos Zambrano vs. Todd Wellemeyer on Saturday and Ryan Dempster vs. Chris Carpenter on Sunday.
Twins at Royals, Friday-Sunday: The Twins took over first place on their homestand, but can they keep it up on the road, which hasn't been kind to them?
Dodgers at Giants, Friday-Sunday: Manny Ramirez makes his first appearance as a Dodger in San Francisco as this rivalry series kicks the intensity level up a notch.
Factoid of the week: The Marlins are on the verge of becoming the first NL team to have four infielders with 20 or more home runs. Entering play on Monday, first baseman Mike Jacobs had hit 22 homers, second baseman Dan Uggla had 26, shortstop Hanley Ramirez had 25 and third baseman Jorge Cantu had 19. Florida would become the first team to accomplish the feat since the 2004-05 Rangers (Alfonso Soriano, Hank Blalock, Michael Young and Mark Teixeira). The Marlins have a shot to become the first team in Major League history with all four infielders sporting at least 25 homers in the same season.
Milestone of the week: Philadelphia's Jamie Moyer, scheduled to start Tuesday night against Florida, has 2,209 career strikeouts. With four more, Moyer will pass Hall of Famer Jim Palmer for 48th place on the all-time strikeouts list.
Jim Molony is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.