DENVER -- The Cubs traded two of their starting pitchers, then Matt Garza was sidelined at the same time with a right elbow injury. They'll be looking to replenish the roster this offseason.

"We certainly need to add a lot of depth over the course of the winter," Cubs general manager Jed Hoyer said Wednesday. "We traded Paul [Maholm] and Ryan [Dempster] and we have to replace those guys going forward."

Maholm was dealt to the Braves, Dempster to the Rangers. Garza (5-7, 3.91 ERA) made 18 starts before he was shut down and has yet to throw since his last start July 21.

"We're certainly hopeful that he's 100 percent but we won't be able to assess that until later on," Hoyer said.

Swinging a hot bat, Castro seeks strong finish

DENVER -- Mathematically, Starlin Castro cannot finish the season with a .300 average. But that's not going to stop him from trying.

Castro entered Wednesday's game batting .326 in September but .284 overall.

"I think about finishing strong," the Cubs shortstop said. "There are eight games left, and I just want to finish strong and be close like last year. Last year, I hit .307. I'll feel good if I hit .295 this year."

There are other numbers which Castro has improved upon. He has set personal highs in triples (12), home runs (14) and RBIs (77).

"I have more homers than last year, more RBIs than last year, more triples than last year," Castro said. "That's what I'm looking for. I want to finish hard. I want to show I can be close to a .300 hitter every year."

Castro doesn't have to hit .300 to impress Cubs manager Dale Sveum.

"If you're .280 to .310, you'll still be in the upper echelons of all baseball," Sveum said.

Barney one game away from error-free record

DENVER -- Chicago's Darwin Barney is now one game away from tying the Major League record for consecutive errorless games by a second baseman.

On Wednesday night at Coors Field, Barney played in his 140th error-free game, and is one away from matching the Major League mark of 141 games, set in 2007 by Placido Polanco with the Tigers.

Barney is rewriting the National League mark each game as he surpassed the old record of 123 games, held by Hall of Famer Ryne Sandberg, who was Barney's former Minor League manager.

Barney leads all NL second basemen in fielding percentage and has made one error this season. His errorless streak is st 1,139 1/3 innings.

Don't expect Darwin Barney to get a day off.

"Barney has the whole winter to rest," Cubs manager Dale Sveum said.

Stewart, Valbuena possibly in mix at third base

DENVER -- Ian Stewart, who underwent surgery on his left wrist in June, was examined on Tuesday, and whether the Cubs re-sign the third baseman for 2013 likely will be determined by doctors' reports.

"Obviously, we'll spend a lot of time getting to the bottom of how it looks going forward before making a decision on his future with us," Cubs general manager Jed Hoyer said Wednesday. "It is a year that's hard to evaluate given the wrist.

"It's challenging," Hoyer said of the decision-making process. "He's got a lot of ability, the same ability that we saw when we traded for him. He's got big power, he's left-handed, he's a really good defensive third baseman. There are a lot of pluses there. We need to figure out what part was the wrist and what part wasn't."

Stewart, acquired from the Rockies in a deal for Tyler Colvin, batted .201 in 55 games with the Cubs before he had to be shut down because of the wrist. He is arbitration eligible.

If not Stewart, then who would be the Cubs' Opening Day third baseman? Luis Valbuena has impressed the Cubs with his defense. Josh Vitters is likely headed to Venezuela this winter to play and challenge for a spot next year, too.

"[Valbuena] is a guy, you look up and see .215, and you think it should be at least .260-ish or something," Cubs manager Dale Sveum said. "It doesn't seem like his average should be that bad. He's given us so many quality at-bats late in games and walks. He's done a really good job -- a great job -- except for that one glaring number, .215, for a batting average."

But is Valbuena good enough to be a regular at third?

"I see him on the team," Sveum said. "He's definitely a quality guy, a left-handed quality utility player who can hit the ball out of the ballpark, give you quality at-bats all the time, catch the ball where he's at. If we don't sign somebody, you could definitely see him [at third on Opening Day]. He's done a heck of a job."