Florida (47-44) at Los Angeles (45-46)

The Los Angeles Dodgers and Florida Marlins are both poised to take advantage of mediocre divisions as they head toward the All-Star break.

The clubs open a four-game series Thursday night when the Marlins make their only visit of the season to Dodger Stadium.

The NL East and NL West are the only divisions that have teams with less than 50 wins leading them, and the Dodgers (45-46) and Marlins (47-44) are in position to capitalize.

Los Angeles joined Arizona at the top of the West on Wednesday by beating Atlanta 2-1 while the Diamondbacks lost 5-0 at Washington.

The Marlins, meanwhile, are tied with New York for second in the East, 1 1/2 games behind first-place Philadelphia.

The Dodgers received an outstanding performance from Derek Lowe on Wednesday as he carried a perfect game into the seventh inning before allowing one run and two hits and exiting with two outs in the eighth. That came two nights after Hiroki Kuroda took a perfect game into the eighth of a 3-0 win over the Braves.

“Our pitching staff has been carrying us all year long,” Dodgers catcher Russell Martin said.

Los Angeles, which swept a three-game set at Florida from April 29-May 1, can reach .500 for the first time since May 30. Right fielder Matt Kemp, who homered Wednesday, went 6-for-15 (.400) with six RBIs in the first series against the Marlins.

Florida improved to 3-4 during an 11-game road trip with Wednesday’s 5-2 win at San Diego. Hanley Ramirez and Mike Jacobs homered for the Marlins, bringing their major league-leading total to 130.

They hope Josh Johnson can start to put his physical problems behind him when he takes the mound for the first time since Independence Day of 2007.

Johnson spent nearly the first three months of last season on the disabled list due to nerve irritation in his right arm. He returned in mid-June and went 0-3 with a 7.47 in four starts before returning to the DL on July 5 with right forearm stiffness.

The 24-year-old right-hander underwent Tommy John surgery a month later.

“I’m not going to try to do too much,” Johnson told the Marlins’ official Web site. “I think last year I tried to do too much. I wanted to help turn it around. It doesn’t work like that. You can only do what you can do. That’s it. You take care of your part, and these guys will take care of their part.”

The Marlins hope Johnson can show some signs of the form he displayed in 2006, when he went 11-5 with a 3.03 ERA in 24 starts after being moved into the rotation.

He hasn’t faced the Dodgers since that season, going 1-1 with a 9.00 ERA in two starts against them.

The Dodgers will give the ball to Chan Ho Park (4-2, 2.36 ERA), who will get his second straight start with Brad Penny still on the disabled list with tendinitis in his right shoulder.

Park has started only four of his 24 games this season, and he’s 1-0 with a 1.29 ERA and 26 strikeouts in 21 innings in those starts.

He was impressive in Penny’s place Saturday, but did not get a decision after yielding one run and three hits while fanning seven in six innings of a 5-2 loss at San Francisco.

Park is 4-3 with a 5.04 ERA in 14 games - 12 starts - against the Marlins.