MILWAUKEE -- Cubs pitcher Andrew Cashner will make his third rehab start on Monday for Double-A Tennessee, then the team will decide if he's ready to move up to Triple-A Iowa.

Cashner, who has been on the disabled list with a strained right rotator cuff since April 6, will be limited to one inning in Monday's outing. After that, Cubs pitching coach Mark Riggins and the medical staff will determine whether the right-hander is ready to pitch out of the Iowa bullpen or if it's better to have him start at Triple-A. By starting, they can give him enough time to warm up before his outing.

If all goes well, Cashner, who turns 25 on Sept. 11, will join the Cubs when they return from a three-game trip to San Francisco, which starts Monday.

Cashner, who won the fifth spot in the rotation this year only to be sidelined after his only start with the shoulder injury, was expected to start in the Arizona Fall League, which begins Oct. 4.

Searching for swing, Soto out of lineup

MILWAUKEE -- Geovany Soto was out of the starting lineup on Sunday to catch his breath.

The Cubs' catcher, who grounded into a forceout as a pinch-hitter to end a 3-2 loss to the Brewers on Sunday, is hitless in his last seven games (0-for-12) and is batting .188 in his last 23 games. What's also discouraging is the high numbers of strikeouts. He's fanned 108 times in 103 games. Last year, he struck out 83 times in 105 games.

"With Geo, [he needs to] continue to work on covering the outer third [of the plate]," Cubs manager Mike Quade said Sunday. "You make a mistake middle in, and he'll make you pay. He's working on the outer third of the plate, whether it's hard or soft, and continuing to work on his breaking-ball approach.

"As you hang around in this league for a while, people will try to get a better feel for you and go to places maybe they didn't early on," Quade said. "It's a constant deal of adjustments. He's got such good pull power, but to stay on the ball, to be able to defend himself away, will determine how good he is down the road. I've seen him do it, and I've played hit-and-run with him a couple times."

Soto is working on that element of his game with hitting coach Rudy Jaramillo. In 2008, when Soto won the National League Rookie of the Year Award, he struck out 121 times but also hit .285 with 23 homers. This year, he's batting .229 with 13 homers and 40 RBIs.

"I've always looked at things in three- or four-year periods and then say, 'This is who this guy is,'" Quade said. "I still think Soto has plenty of room to improve and can have those kind of years like he did last year and his Rookie of the Year, year, but he's got to make adjustments now."

DeWitt likely to start opener in San Francisco

MILWAUKEE -- Blake DeWitt may get a start on Monday. He's one of the few Cubs who has had success against Giants pitcher Tim Lincecum.

DeWitt is 8-for-18 against the Giants right-hander. That's not much of a sample size, but the rest of the Cubs combined have 12 total hits against him. DeWitt had no explanation.

"He's obviously one of the best, if not the best in the league," DeWitt said. "When you win the Cy Young like that, and that early in his career, you know he's in a special class of pitcher."

Lincecum has won the top pitching award twice, in 2008 and '09.

"He's explosive," DeWitt said. "The ball really jumps out of his hand, and he's deceptive. If he's throwing 92, 93 [mph], it looks like 96, 97. That's one of the reasons he's had so much success."

Lincecum is 12-10 with a 2.46 ERA, and the Cubs will counter with Randy Wells (5-4, 5.53 ERA).

Extra bases

• Interim general manager Randy Bush, manager Mike Quade and player development director Oneri Fleita will meet Friday in Chicago to discuss which players will be added when rosters expand Sept. 1.

The Cubs' Minor League teams wrap up their seasons next weekend. Among the players expected to be added are first baseman Bryan LaHair, who was batting .330 with 36 homers and 105 RBIs for Triple-A Iowa.

• One thing Quade would like to see from both Tony Campana and Darwin Barney is to be more selective at the plate and take advantage of their speed. That means they have to get on base.

"I think a huge thing for 'Campy' down the road is to get stronger," Quade said Sunday. "Don't touch his legs, but if he can get stronger, he can drive the ball a little more. If he can get the outfield to respect his swing and do some things, that will be huge."

Quade also told Barney in Spring Training that the second baseman will thrive if he can lay off the high fastballs.

"His swing is good enough," Quade said of Barney. "If he can add that discipline on a regular basis, it will put him in favorable counts and keep the ball out of the air. He's such a good mid-thigh, low-ball hitting guy."

Quade also is impressed with how hard Barney battles during at-bats.

"He's just geared, 'I'm not striking out,'" Quade said.

• Aramis Ramirez finished Sunday with a .409 batting average in August, while teammate Reed Johnson was batting .393. Ramirez began the day hitting .427 and was tied for tops among Cubs players in the month of August, dating to 1946. Shawon Dunston batted .427 in August 1991; Bill Madlock hit .425 in August 1975; and Manny Trillo hit .409 in August 1986.