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04/21/2013 8:10 PM ET

Braun knows what Sveum expects of Cubs

MILWAUKEE -- Ryan Braun hit a three-run home run Sunday to help the Brewers beat his former hitting coach and current Cubs manager Dale Sveum. Fourteen of the Cubs' 17 games this season have been decided by three runs or less, and it's been tough for them to overcome any mistakes.

"I'm sure he's frustrated," Braun said of Sveum, now in his second year as Cubs manager. "I think he always expects his teams to be fundamentally sound, he always holds guys accountable. We loved having him here and I'm sure they enjoy having him over there, but obviously, it's a frustrating time. All three of their starters threw the ball well against us, it was just a matter of making a couple of mistakes that ended up hurting them."

The Cubs actually out hit the Brewers, 22-16, in the three-game series, yet were swept.

"Those three games can turn around and go either way, so that part's frustrating [for Sveum]," Milwaukee manager Ron Roenicke said. "We went through it early in the season, and most likely, we're going to go through it again during this season. It's the ups and downs, and at the beginning of the season, for me, that's harder. But they've got enough guys -- their starting pitching is good, and I think they'll be all right."

Castro increases hitting streak to NL-best 13

MILWAUKEE -- The hits keep coming for Cubs shortstop Starlin Castro, who singled to center with two outs in the third inning Sunday to extend his hitting streak to 13 games, the longest active streak in the National League.

Castro now has eight hitting streaks of 10 or more games since the start of the 2011 season, tied with the Yankees' Robinson Cano for the most during that stretch.

Since he made his big league debut on May 7, 2010, Castro has totaled 550 hits, the most in the NL in that span. Milwaukee's Ryan Braun was second, entering Sunday's game with 538 hits.

Sveum expresses frustration with team's sloppy play

MILWAUKEE -- Manager Dale Sveum is losing patience with the way the Cubs have played recently, and the players can understand that.

"I think everyone is losing a little patience," Anthony Rizzo said Sunday. "Everyone needs to have fun. That's the main thing -- have fun and everything will take care of itself."

The Cubs headed into Sunday's series finale against the Brewers having won three of the last 13 games. They are among the Major League leaders in errors, adding three more Saturday in a 5-1 loss, and also have the lowest batting average in the Majors with runners in scoring position. They're wasting solid starting pitching. Chicago's starters have a 3.19 ERA, fifth lowest in the National League.

The errors are both physical and mental, and are a surprise after how well the Cubs played in Spring Training, Sveum said.

"Some of these errors, they look physical but they're maybe a lack of awareness at the time or the situation at hand or they're trying to be too quick, or sometimes we don't have enough aggressiveness on balls or whatever it is," said Sveum, whose voice was hoarse after his argument with an umpire Friday that resulted in him being ejected. "Sometimes defense is a rhythm and we're obviously not in any kind of defensive rhythm. Just like offense can be contagious, defense can, too.

"From top to bottom, we did outstanding in Spring Training, so to start out like this is obviously disappointing," Sveum said. "The bad thing is we're not picking each other up after these things happen.

"We're not overcoming our mistakes," Sveum said. "Good teams overcome those mistakes. A guy gets a ground ball double play and nobody thinks about what just happened."

Rizzo was charged with an error Friday and bobbled a ball on Saturday.

"We've got to make those plays and I think people are maybe putting too much pressure on themselves to make the plays," Rizzo said. "It's a long season and we need to start having more fun. Everyone says we're young -- let's play and have fun like we're young, too. Take it one pitch at a time."

Sveum said they can make changes if players don't perform.

"You find options," he said. "If people keep playing like that, you have to find options and give people playing time in Triple-A to figure this stuff out."

He's looking for more consistency, game-changing plays, and better performance on the field.

"You have to perform," Sveum said. "The bottom line is you have to perform. Whether they need more development, you decide all those kind of things."

And no one, he said, is invincible.

Extra bases

• Cubs pitcher Matt Garza threw a bullpen session Sunday at Miller Park, and the next step will be a Minor League rehab start for Double-A Tennessee.

Garza, coming back from a strained left lat sustained in mid-February, threw two innings on Friday, the first time he was in a game situation since the injury.

• Ian Stewart, who missed all of Spring Training with a strained left quad, played nine innings for Triple-A Iowa on Saturday and now is 1-for-13 with eight strikeouts and three walks in four Minor League games.

"We're not in a big hurry," Cubs manager Dale Sveum said of Stewart's return. "[Luis] Valbuena has been one of our most consistent players defensively and offensively and he's getting his walks. He's doing a great job. There's no real urgency. [Stewart] has got to go down there and get hot swinging the bat."

The Cubs are a little short in backup infielders with only Cody Ransom available. If necessary, Sveum said catcher Welington Castillo could sub in the infield.

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.