(My Sportsbook) - Like a stunned fighter, the first place Chicago Cubs are suddenly on the ropes in the National League Central. Without Sammy Sosa on the field, the Cubs have struggled and it has opened the door for the rest of the competitors in the division.

The Astros, which reside just 1 1/2 games behind the stumbling Cubs, have a golden opportunity this weekend with three contests at Minute Maid Park against the front-runners.

With a sweep, the Astros could replace the Cubs atop the division and send a message at the same time. It's still early in the season, but grabbing the top slot would be huge for Jimy Williams' club.

Houston continued its solid play as of late on Thursday, as it posted a 5-2 victory in the rubber match of its series against the rival St. Louis Cardinals.

Jeff Kent and Richard Hidalgo each drove in a pair of runs for the Astros. Hidalgo and Adam Everett each had solo homers in the winning effort.

Jeriome Robertson (2-3) posted the win for Houston, allowing one run on four hits in 5 2/3 innings of work. He struck out four and walked none in the victory. Robertson shook off his six-game winless (0-2) streak to gain the win.

"I'm not thinking now," Robertson said. "I'm just letting Zaunie [catcher Gregg Zaun] call the game. I'm not worrying about what I need to do with a hitter. I just throw whatever he wants and where he wants it. Zaunie and I are on the same page. I know what he wants most of the game,"

Billy Wagner notched his 12th save of the year. Wagner picked up his 193rd career save, moving him ahead of Mitch Williams for fifth place on the all- time saves list for lefthanders.

The Astros will try to build on the momentum on Friday night versus the Cubs, but it won't be easy with stud sophomore Mark Prior on the hill. Prior is 3-0 over his last six starts, but has registered just a 1-2 mark with a 4.45 ERA in five career games versus Houston.

Houston will reply with 26-year-old righthander Scott Linebrink on the mound. Linebrink is without a decision in his last six contests, including an outing versus Philadelphia last week. The twirler allowed five hits and three runs through five innings, while walking four and fanning two.

Linebrink has no record with a 6.75 ERA in three career outings versus the Cubs. This season, Linebrink is 0-0 with a 4.80 ERA in three contests at home.

The Astros went 11-8 against the Cubs last season, including 5-4 at home. Over the last three seasons, Houston is 27-21 versus the Cubs.

WHO'S HOT

Everett has been very good in the last three games, posting six hits in his last 12 at-bats (.500). His batting average has climbed 46 points to .306 on the season. During the stretch, Everett has hit a homer, knocked in two runs and scored two runs.

WHO'S NOT

Things haven't improved all that much lately for Lance Berkman. The 27-year- old leftfielder is just 5-for-29 (.172) in his last eight contests. He has tallied no homers and just two RBI.

COMING UP

The Astros finish up their nine-game homestand against the Cubs this weekend. After the weekend, Houston hits the road for seven straight against St. Louis and the Cubs.