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5/11/2013 8:45 P.M. ET

Valbuena exits game with jammed pinky

WASHINGTON -- X-rays were negative of Cubs third baseman Luis Valbuena's right little finger, injured when he slid into third base, and he was not expected to have to go on the disabled list.

Valbuena had to leave Saturday's game against the Nationals after jamming his hand sliding into third base. With one out in the fifth against the Nationals, Valbuena doubled to right but was tagged sliding into third trying to stretch his hit. Cody Ransom took over at third base in the sixth.

Cubs manager Dale Sveum said there was no fracture and Valbuena most likely can't play in the field, but would be available to pinch-hit. Valbuena was not scheduled to start Sunday against Nationals lefty Gio Gonzalez anyway.

Valbuena was batting .272 with five home runs and 13 RBIs.

Cubs pitchers struggling with fielding their position

WASHINGTON -- Cubs pitchers took plenty of grounders in Spring Training, and they have also done some early work during the regular season. But they headed into Saturday's game having committed eight errors, which is as many as the entire Diamondbacks team.

"Half of our [total] errors are from our catchers and pitchers," Cubs manager Dale Sveum said Saturday. "It's incredibly strange."

There isn't a pattern either.

"Every error has been a different kind of error, too, whether it's throwing to first, throwing to second, a little dribbler to the mound," Sveum said. "We've thrown some balls into center field. Between the errors by pitchers and [being] second in the National League in walks and hit batters, that just adds up to way too many people on base. And the bottom line, like I keep saying, is when we make that mistake, we cannot seem to make a pitch after that."

That happened on Friday, as Jeff Samardzija's fielding error led to two runs by the Nationals in a 7-3 loss.

So, if the Cubs do the drills, why are they making the mistakes?

"It's hard [to explain], because we have really good athletes who are pitching," Sveum said. "We're not dealing with guys struggling with their athleticism. Hopefully, it's over with and that's the last we're going to see.

"Sometimes, the players just have to be able to perform in these situations. If you're a big league player, you have to be able to perform on the stage. It's like taking [batting practice] and ground balls; you can do that all day long and never make an error, but you have to be able to do it in games."

Garza to be evaluated after one more rehab start

WASHINGTON -- Cubs pitcher Matt Garza gave up three hits and walked two over 3 1/3 innings Saturday for Double-A Tennessee in his third Minor League rehab start.

Garza threw 66 pitches, 40 for strikes, and struck out two.

Manager Dale Sveum said the right-hander will make at least one more rehab start for Triple-A Iowa in five days, and then be re-evaluated. Garza is coming back from a strained left lat suffered in mid-February during live batting practice.

The plan Saturday was to have Garza throw 65 to 75 pitches. He needed 30 pitches to get through the first inning.

The Cubs are not going to go with a six-man rotation when Garza returns, which means someone will get bumped. Sveum said it won't be Edwin Jackson, despite his early season struggles.

Jackson entered Saturday's game against the Nationals with an 0-5 record and a 6.39 ERA, while the other four starters rank among the top 15 pitchers in the National League in opponents batting average against. The right-hander fared better against the Nats, allowing two runs in 5 1/3 innings to lower his ERA to 6.02.

Carlos Villanueva has done well as a starter this season and has never had the chance to make 32 starts. His single-season innings high is 125 1/3, set last year.

Cubs hope Stewart has a future with organization

WASHINGTON -- The Cubs may have taken Ian Stewart off the 40-man roster, but they are hoping the third baseman can get back on track and contribute.

Stewart missed all of Spring Training because of a strained left quad suffered in the first intrasquad game on Feb. 21. After his Minor League rehab time ended, Stewart was activated from the disabled list and then optioned to Triple-A Iowa. In 15 games, he was 4-for-46, while Luis Valbuena has done well playing third for the big league team.

"We've been really patient with him," Cubs general manager Jed Hoyer said Saturday. "Early in the rehab, you take numbers with a grain of salt, but I think later on, I think you've got to perform, especially with Valbuena doing what he's doing. We'd be jumping up and down to get that kind of performance out of a third baseman. Valbuena has earned that job."

Stewart now seems to be behind Josh Vitters on the depth chart at third base at Iowa. Hoyer said it would be a "disservice" to not play Vitters, who was the team's No. 1 Draft pick in 2007.

Is there a future for Stewart in the Cubs organization?

"I'm not sure," Hoyer said. "I hope there is. I do think there's a lot of talent there. It's been an unfortunate run with the injuries. He's a left-handed hitter with power who plays good defense. I hope there's a future here, but at this point, it's going to be about performance. We want him to perform."

Struggles continue with runners in scoring position

WASHINGTON -- The Cubs lead the National League in extra-base hits, yet they are last in the Major Leagues with runners in scoring position. Friday's game against the Nationals was a perfect example of their struggles at the plate. The Cubs collected a season-high seven doubles, yet went 2-for-14 with runners in scoring position in a 7-3 loss.

"It's hard to score only three runs with seven doubles," Cubs manager Dale Sveum said Saturday.

"That's nearly impossible," general manager Jed Hoyer said.

The approach that batters must have, Sveum said, is to remember that the pitcher is the one on the ropes, not the batter.

"So much of our struggle scoring runs is attributed to two things," Hoyer said. "We don't get on base enough, and we don't drive guys in when they're in scoring position. You keep waiting for that to turn around."

The Cubs rank 12th in the National League in on-base percentage and are 11th in runs scored.

How do they fix it?

"A lot of times, it's a cycle-type stat," Sveum said. "The Angels, as great a lineup as they have, have struggled in that situation. It's a little bit contagious, and hopefully, by the end of the year, [the Cubs numbers] get to be respectable."

Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.