CHICAGO -- The Cubs may finally have their 25-man roster the way they want it.

Alfonso Soriano showed why he's a key part Tuesday when he smacked a three-run homer with two outs in the seventh, his 20th, and added an RBI single in a four-run second to power the Cubs to an 11-7 come-from-behind victory over the Houston Astros.

Chicago trailed, 7-6, against Chris Sampson (5-4), entering the bottom of the seventh. Reed Johnson singled to lead off the inning and reached third on Mark DeRosa's second double and third hit of the game. Kosuke Fukudome hit a sacrifice fly to tie it, and pinch-hitter Daryle Ward was intentionally walked. One out later, Doug Brocail faced Soriano, who launched a 1-2 pitch into the left-field bleachers.

"I like those moments," Soriano said.

"He changes the game with one swing," DeRosa said of the Cubs' leadoff man. "He's one of the big superstars in the game. He's one of those guys, I think more so than his ability to hit the ball out of the ballpark, but he loosens us up as a team with his charisma and character in the dugout.

"He's a huge part of who we are, and I don't want to say he's our spark plug, because he bombs the ball out of the park," DeRosa said. "But at the same time, he gets us going."

The Cubs scuffled when Soriano was on the disabled list for six weeks because of a broken bone in his left hand. In his past 10 games, he's hitting .419 (18-for-43) with two doubles, five homers, 12 runs scored and 11 RBIs. The Cubs are 8-2 in that stretch.

Monday's series opener was interrupted twice by lightning and heavy rain, and finally stopped after 8 1/3 innings, with the Astros winning, 2-0. On Tuesday, there was nothing but sunshine, coupled with the return of Kerry Wood, activated from the disabled list earlier in the day. He pitched the eighth, with the Cubs' easing him back into the closer's role.

"It's great to be back," Wood said.

"The roster's fine," Cubs manager Lou Piniella said. "We felt that once we got Soriano back, that he would stabilize our offense, and he has. Now that we have Woody back and can get him throwing the way he's throwing, our bullpen falls into the situation that we really like. We just have to keep playing."

There are still some adjustments to be made, such as learning what starter Rich Harden can and cannot do. He struck out eight over 5 2/3 innings, and gave up five runs on eight hits. Acquired July 8 from Oakland, the right-hander had given up three runs in 24 1/3 innings in his four previous outings with the Cubs.

Harden also had a bunt single, and confessed to Piniella in the sixth that his legs were a little tired.

"I felt good early," Harden said. "I don't like making excuses for myself, but I missed some pitches, left some balls up. My offspeed I wasn't throwing for strikes, and they were sitting fastballs. If I'm not locating that pitch, they're going to hit it."

Then there's reliever Bob Howry, who served up a go-ahead home run to Carlos Lee in the seventh. Piniella had gone out to talk to Howry before Lee's at-bat.

"They wanted to pitch to him," Piniella said. "Lee can hit. I had choices, and obviously, the right one wasn't chosen."

Tuesday was the Cubs' 19th straight game, and the bullpen is a little spent. Off-days on Thursday and Monday could not come at better times. Speaking of breathers, DeRosa and Derrek Lee came back refreshed after a day off. DeRosa had three hits and three RBIs, and Lee notched his first extra-base hit since July 28 when he doubled in the first. He had four hits for the first time since June 28.

"I take my day and try to relax," DeRosa said of the time off. "I understand the reasons why he gives them. I've been scuffling at the plate and trying to do too much, and today was a nice day to build off."

Chicago batted around in the second against Houston starter Wandy Rodriguez to open a 6-1 lead, and scored on an RBI single by Soriano, a bases-loaded walk to Aramis Ramirez, a sacrifice fly by Johnson, and an RBI single by DeRosa.

The Astros rallied, closing the gap to 6-5 on Geoff Blum's two-run homer with one out in the sixth. Carlos Lee then connected on his 26th homer with two outs in the seventh off Howry to go ahead, 7-6.

"You want to come back for your teammates," DeRosa said. "Rich will tell you he probably didn't have great command of his offspeed pitches. When you get a chance to sit on heaters, it doesn't matter how hard you throw, Major League hitters are going to find a way to put the bat on the ball. Same with Bobby. No one wanted to get Carlos Lee out bigger than Bobby did.

"When it doesn't happen, you want to pick them up, because there's been times when we've been picked up by our pitching staff as well."

Sounds like something good teammates would do.