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9/20/2013 2:02 P.M. ET

Castillo needs knee surgery, done for season

CHICAGO -- Welington Castillo has a partial meniscus tear in his right knee and will need arthroscopic surgery, meaning the Cubs catcher won't return for the remainder of this season.

Castillo, who had an MRI on Friday, exited Thursday's 5-1 victory over the Brewers in the sixth inning after running out a ground ball.

"With proper rehab, it's the type of thing you come back 100 percent from with rehab," Cubs president of baseball operations Theo Epstein said.

A conservative estimate for the rehab timetable is four to six weeks following surgery. A date for Castillo's surgery was not announced.

"He had a fantastic year," Epstein said. "I think it's a developmental success story in every facet. With catching, it starts with winning the trust with your pitchers and putting the right fingers down, and he did an outstanding job. He's really involved in game planning and game calling. I think every pitcher now loves throwing to him. He did an outstanding job defensively. His blocking has been at an elite level."

Epstein added that despite a slow start to the season offensively, Castillo -- who was hitting .271 with 23 doubles, eight home runs and 32 RBIs in 380 at-bats -- made the necessary adjustments and finished strong.

"He made some adjustments and learned a lot about his swing and has gotten pitches that he can drive and is doing damage with them," Epstein said. "He's always been a super-talented player and great kid, and this is one of those years he's established himself. Unfortunately, it ends this way, but he had a full year."

Epstein clarifies remarks on Sveum evaluation

CHICAGO -- Theo Epstein said Friday he understands the speculation about Dale Sveum's status after the Cubs president of baseball operations said the manager was being evaluated, but he added the review is a normal process.

Sveum is finishing his second season as the Cubs manager and has one year remaining on his contract, with an option for 2015. On Tuesday in Milwaukee, Epstein would not confirm whether the manager was returning next year.

"I gave an answer that could be interpreted a number of different ways," Epstein said Friday at Wrigley Field. "The bottom line is we have a process at the end of the year, unless it's been a perfect season and everyone gets pats on the back. Until we get to where we want to be as an organization, everyone, including myself, gets evaluated and we look to find places where we can do things better next year."

Speculation has begun in the Chicago media on who would possibly succeed Sveum. Epstein dismissed talk about any names.

"We wouldn't be doing our job if there wasn't an evaluation process," Epstein said. "I totally understand that [for the media] it became a story. We answer questions honestly. Is anyone definitely coming back? At this point, well, no, because we're in the midst of an evaluation process.

"That's really standard for this time of year," he said, "and it'll be resolved quickly after the season and we'll move forward. I'm proud of a lot of what Dale and the staff have accomplished with the big league team this year in certain areas."

A decision could come as early as Sept. 30 when Epstein, Sveum and the coaching staff are expected to meet in Chicago.

Sveum: Cubs can learn from teams' celebrations

CHICAGO -- With the Cubs opening their final homestand of the season on Friday afternoon against the Braves and scheduled to play their final six games against the Pirates and Cardinals, it's possible that a postseason berth celebration could take place after one of those contests.

Manager Dale Sveum said that while his club never wants to lose a game, he didn't think having a team celebrate after defeating the Cubs would necessarily be a bad thing for some of the younger players to witness.

"It's a bad thing that you lost that game where [another team] clinches," Sveum said. "But it's not a bad thing to see people celebrate when you haven't done it. To see it in person, it kind of hits hard in your stomach and you want to be that guy. And sometimes it works in your advantage, too."

As for the Dodgers' celebration after clinching the National League West title in Arizona on Thursday -- which involved jumping into the swimming pool beyond the right-field wall at Chase Field -- Sveum said he wouldn't have gone that far.

"I don't know if I would've appreciated it," he said.

Extra bases

• Reliever Daniel Bard, whom the Cubs claimed off waivers from the Boston Red Sox on Sept. 4, will probably not appear in a game before the end of the season.

The 28-year-old was 10-19 with a 3.67 ERA in 211 appearances (10 starts) with the Red Sox from 2009-13. Boston attempted to convert him to a starter before the 2012 season, but the right-hander struggled and spent most of the past two seasons in the Minor Leagues. He also suffered an abdominal strain that sidelined him for much of last season.

"I don't think we'll see him in the last nine games," Cubs manager Dale Sveum said. "He's still in the process of throwing his side sessions and getting a feel for pitching and getting completely healthy and getting built up to see what happens going into Spring Training."

• Going into Friday, Welington Castillo led all Major League catchers with a 2.8 defensive WAR for the season.

First baseman Anthony Rizzo went into Friday's game leading all Major League first basemen with a 0.5 defensive WAR.

Second baseman Darwin Barney went into Friday's game with the second-highest defensive WAR among National League second basemen (1.4) and his .993 fielding percentage was the best among NL second basemen.

• Entering Friday, outfielder Junior Lake led all Major League rookies with 66 hits since the All-Star break.

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