HOUSTON -- There was no turnover Monday at the top of the Cubs' batting order as manager Dale Sveum hinted he might do.

"I didn't say I was changing it," Sveum said. "I considered it. I decided not to."

Why not? Part of the reasoning is Sveum wanted to overload the lineup with left-handed hitters against Astros right-handed starter Bud Norris. The other reason is the Cubs will face left-handed starters for three games, beginning Tuesday, and he'll be using his right-handed-hitting lineup for those games.

But Sveum did come close to some tweaks.

"Very close, I will admit," Sveum said. "I decided to give it one more week, the right-handed lineup."

It isn't that Sveum is upset at the job David DeJesus, Tony Campana and Starlin Castro are doing in the 1-2-3 spots. The Cubs haven't been able to turn the lineup over. They're batting .231 with runners in scoring position.

"The bottom line is we're still not scoring runs," said Sveum, whose team ranks 14th in the National League in RBIs. "We're not scoring runs off the starting pitchers and it's been going on all year. It's kind of weird. We're better against the back end of the bullpen than we have been against starting pitchers."

For example, in the three games against the White Sox, all losses, the Cubs were outscored 16-6, and only two of those runs came off a starter, Philip Humber.

"I think the top three, we're doing a decent job getting on base for the guys behind us," DeJesus said. "[Sveum] knows what he's doing. We trust him, we stand behind him and whatever he has in store for us, we'll deal with it and go out and do it."

After nearly two months, Sveum is looking for more production.

"You want to see adjustments," he said. "As players and hitters go, you want to see the effort, and I don't care if you stand on your head, just understand that when you get to a certain stage of at-bats, that it's time to change something. ... Cal Ripken used to have a different stance every week, [so did] Don Mattingly -- you go on and on.

"You just want to see some effort for change, whether it's mechanics or the effort to take more pitches and not feel like the only way you have a chance is to hit the first pitch and if you don't, the at-bat is over," he said. "These kind of things are what you want to see changed and adjustments made that way."

What Sveum has seen are eight good at-bats by players, then eight not so good at-bats. It's weird, he said.

"When you get to the two-month mark of the season, that's when things start to change," Sveum said. "It becomes, 'OK, we've given you the opportunity and given you the chance, we have to get production now.' There are people waiting in the wings to get jobs."

Wood back for extended stay in rotation

HOUSTON -- Travis Wood could pack for a longer stay with the Cubs this time.

Wood, who made a spot start May 6 for Matt Garza, when he was ill, will step into the rotation on Tuesday against the Astros, filling Chris Volstad's spot.

"I've been throwing the ball pretty well down there and hopefully it translates up here and I just go out and give the team a chance to win every fifth day," Wood said.

He has not been officially added to the Cubs' 25-man roster. The team will make a move on Tuesday.

"Hopefully, I'm able to stick around for a while this time," Wood said.

All he needed was an overnight bag when he joined the team to start May 6. He gave up three runs on three hits over six innings and the Cubs notched a win over the Dodgers. At Triple-A Iowa, Wood was 3-3 with a 4.57 ERA, but 2-0 in his last two outings.

"I think I just relaxed, quit pressing," said the lefty, who was optioned back to Iowa after the outing. "The pitches are there. I have to just quit trying to make them too good and just let them work."

Cubs manager Dale Sveum said Wood may have been trying to impress his new team too much. Wood admitted that may have been a problem. Now, he just wants to relax and pitch.

"Whatever's going to happen is going to happen," he said. "You just have to keep that mindset and stay relaxed. Once the ball leaves my hand, I have no control over it, so just try to make the pitch the best I can and see what happens and let the guys behind me do their job and see what happens."

Wells 'excited' for opportunity to help every day

HOUSTON -- Randy Wells couldn't wait to get in a game, and he got his chance Monday in an 8-4 loss to the Astros.

Wells had yet to make an appearance since being called up Saturday from Triple-A Iowa. He got an opportunity Monday, pitching five innings in relief of Matt Garza, who gave up seven runs in three innings against the Astros. Wells was charged with one run on three hits. That run came on a solo homer by Jed Lowrie in the seventh.

The right-hander was eager to get started in his new role as a relief pitcher.

"It gives me a chance to help the team and do something a little different," Wells said Monday. "Who knows? Maybe I'll be good at it."

At Iowa, Wells was 2-2 with a 7.71 ERA in six starts. He has been used as a starter the last three seasons but will try life in the bullpen for now.

"One thing I like is the chance to play every day," the right-hander said. "I've [pitched in relief] my whole career until 2008. It's something I'm comfortable with. I'm actually excited."

Extra bases

• Starlin Castro had two hits Monday, and now has 400 through the first 325 games of his young career. Among all Major League players who started their careers after 1980, Castro is tied for sixth-fastest to reach 400. The players ahead of him are Ichiro Suzuki (268 games), Nomar Garciaparra (302 games), Kirby Puckett (310), Hanley Ramirez (317), Wade Boggs (324) and Alex Rodriguez (325).

• Reliever Blake Parker, still bothered by some tightness in his right hamstring, was not available on Monday. His status is day to day.

• Catcher Welington Castillo, out with a sprained right knee, was able to throw but was not available to pinch-hit, which left the Cubs shorthanded starting the series against the Astros.

• Don't expect to see Dale Sveum on Twitter.

"I wouldn't know what twitting is, I wouldn't know how to even start it, or Facebook, no," the Cubs manager said.

He uses two fingers to type on the computer keyboard but he can send a text message. It's the only way sometimes to communicate.

"That's the only way to do it -- then you don't have to talk on the phone," Sveum said. "When you have kids, you learn how to text, especially a daughter. That's the only chance I have to talk to her."