HOUSTON -- Regardless of who the Cubs have put in the leadoff spot this season, they have been productive, leading the National League in batting average and on-base percentage.

But Cubs manager Mike Quade has been excited about hitting Starlin Castro at the top of the order and Darwin Barney second. In the three-game series at Houston, the pair batted 1-2 all three games.

On Wednesday, Castro went 3-for-5 with a run, giving him eight hits in the series, and Barney went 2-for-4 with an RBI double and a run.

After Wednesday's game, Castro is hitting .389 and Barney .345.

"I like the two kids at the top right now," said Quade. "They're having fun, they're playing well. If they happen to set the table, it's pretty good behind them."

Castro, Jeff Baker and Kosuke Fukudome have all batted leadoff four times this season. Entering Wednesday, Cubs leadoff batters were batting .467 with an on-base percentage of .538.

Baker licks chops when facing lefties

HOUSTON -- Jeff Baker was in the starting lineup at first base for Wednesday's 9-5 win over Houston, replacing the slumping Carlos Pena, who is batting .185.

The right-handed-hitting Baker, who has been feasting on left-handed pitching, did so again against Astros left-hander Wandy Rodriguez.

In three at-bats against Rodriguez, Baker went 2-for-3, including a two-run double that was part of Chicago's five-run first inning.

By playing Baker, who appeared at first, second and third base this spring, the Cubs gave Pena consecutive days off, with Thursday's off-day before beginning a three-game road trip at Colorado on Friday.

Since the start of the 2010 season, Baker is hitting .367 (58-for-158) against left-handed pitching.

On Wednesday, Baker, who has hit in the leadoff spot four times this season, batted from the five-hole for the first time in 2011.

Quade on pitching: All hands on deck

HOUSTON -- The Cubs haven't nailed down who will get the start on Tuesday at home against San Diego. If Jeff Samardzija gets the spot start, it definitely wouldn't be a long-term option, Cubs manager Mike Quade said on Wednesday.

Samardzija, who has five Major League starts, has found his role as a reliever. In Tuesday's 11-2 loss to the Astros, Samardzija gave the Cubs three innings out of the bullpen after James Russell's first Major League start lasted only 1 2/3 innings.

"For one start it's not out of the question," said Quade. "I would like to avoid that, but long term no, I don't think he's an option. He's most likely to be effective out of the bullpen."

The Cubs are looking for a No. 4 and No. 5 starter since Randy Wells and Andrew Cashner were put on the 15-day disabled list. Wells is retroactive to April 5 with a right forearm strain, and Cashner is retroactive to April 6 with a right rotator cuff strain.

"For the next week or so, it's all hands on deck," said Quade.

The starting pitching options include players on the big league roster or players at Triple-A Iowa, including Ramon Ortiz, a two-time 15-game winner who signed a Minor League deal last week, and on Monday allowed two runs in 5 2/3 innings at Iowa.

The good news is the Cubs have nearly a week to figure out who they want to start on Tuesday.