CHICAGO -- Cubs catcher Geovany Soto was not available to play in Saturday's 4-3 loss to the Reds because of a mild ligament sprain in his right shoulder.

Soto's shoulder bothers him when he's hitting, not throwing. He was not expected back in the Cubs' lineup until Monday at the earliest.

"We were down to one catcher, Soto wasn't available," Cubs manager Lou Piniella said. "We couldn't even pinch-run for our catcher when we bunted. We had chances in the ninth with the middle part of the lineup and didn't get it done."

Koyie Hill caught Saturday and will be behind the plate Sunday as well.

Scuffling Colvin gets day out of lineup

CHICAGO -- Tyler Colvin planned on taking advantage of an off-day Saturday to do a little homework.

The rookie outfielder was not in the starting lineup Saturday. He's 2-for-17 on this homestand including a critical at-bat Friday. The Cubs had two runners on and one out in the fifth inning when Colvin came to bat against the Reds' Bronson Arroyo. Colvin popped up to short, and the Cubs eventually lost, 3-0.

"Colvin has a tendency to widen the strike zone for himself," Cubs manager Lou Piniella said after Friday's game. "That's something he'll have to learn if he wants to be a really good professional hitter and RBI guy. It's something young players have to go through and learn."

It wasn't pitch recognition that was the problem, Colvin said Saturday.

"It's just relaxing up there and being confident," he said. "I go up there and I want to find a good pitch to hit with men on base. Usually that's what I do. Lately I've been getting in those situations and I'm getting anxious and swinging at pitches out of the zone that they want me to swing at, not what I want to swing at."

Colvin knows that's not what he's supposed to do.

"You're not supposed to swing at balls," he said.

So if the problem isn't a matter of seeing the strike zone, what is it?

"It's not recognition -- it's being over-anxious and making my mind up to swing before I even know what pitch is coming," Colvin said.

Does he need to take deep breaths?

"I need to take a step back when I know I'm anxious," Colvin said. "I need to step out, regroup and go back at it. I'm having a hard time doing that."

The day off can help.

"I can talk to [hitting coach Rudy Jaramillo] some more, talk to Marlon [Byrd] and see what I can get from them," Colvin said.

Week has been a busy one for DeWitt

CHICAGO -- Sunday marked the one-week anniversary since Blake DeWitt joined the Cubs, and so far, he's adjusted to mornings, his new teammates and second base.

"It's been a good first week for me as far as feeling comfortable here and getting to know the guys," DeWitt said Saturday.

Acquired from the Dodgers on July 31 for Ted Lilly and Ryan Theriot, the 24-year-old second baseman actually came up as a third baseman.

"There are a lot of aspects of second base I need to work on -- it's still new to me," DeWitt said. "I feel comfortable enough over there. I've had enough games under my belt over there to realize I like playing over there.

"It's been a work in progress," he said. "I've made some strides this year, but there is still a lot of stuff to work on."

Cubs bench coach Alan Trammell said he's pleased so far with DeWitt's play and eagerness to learn.

"They've been able to show me things and we'll talk about plays that happen in the game -- it's a lot of help," DeWitt said of Trammell and coach Ivan DeJesus.

Does he miss L.A.?

"The thing you miss is your teammates," he said. "I'm excited to be here, and I'm excited about this opportunity and this is a great place to play."

However, that first stretch of day games is an adjustment.

"You're worn out after a day game, so it's easy to go home, sleep and get up for the next day," DeWitt said. "Sometimes it's kind of nice having the evening off and you can do something with family."

Extra bases

Cubs outfielder Kosuke Fukudome has hit safely in his last three games, but his starts have been few and far between. "I'm just preparing myself for each and every day to just play," said Fukudome, who started Saturday for the first time since July 28 and was 1-for-2 with three walks and scored a run. "It's not my decision to make whether I'm going to start or someone else is going to start. I just see the lineup and who is starting and that's about it." ... Cubs reliever John Grabow traveled to Mesa, Ariz., on Sunday to begin the first phase of his rehab assignment. Grabow, on the disabled list since June 29 with a sprained left knee, was to throw in a game with the Cubs' Rookie League team and will eventually join either Double-A Tennessee or Triple-A Iowa for at least two appearances. The Cubs can use the experience. They have five rookies in the bullpen. ... Jeff Samardzija is 9-1 with Triple-A Iowa. ... Starlin Castro entered Saturday batting .413 since July 10, which ranks second in the Major Leagues. Houston's Chris Johnson leads all players with a .423 average. ... Carlos Silva is on schedule to undergo a diagnostic cardiac test Monday at Northwestern Memorial Hospital. He came out of his last start with an abnormal heart rate. ... WGN Radio's Ron Santo, who is limiting his travel some this season for health reasons, will miss the Cubs' upcoming trip to San Francisco and St. Louis. Dave Otto will fill in.