"[Castro] is a guy who is going to be as good as he wants to be, and adjustments are still part of his game, as well," Sveum said Wednesday. "Sometimes you have kids like that, and they may never have gone through any adversity on the offensive part. Sometimes guys learn how to pitch to you, so you have to make those adjustments, or you have to make adjustments in your hitting style to get better and not be content with being OK with a .720 OPS or whatever it is. Adjustments are how you do that sometimes."
In his last 12 games, Castro, one of the Cubs' two All-Stars, was batting .196 (9-for-46).
Backup catcher Steve Clevenger was batting .449 at home, and .127 away, which would make one think that the catcher should be in the lineup for every Cubs game at Wrigley Field.
"[Geovany] Soto is swinging the bat pretty good, and as good as he has all year," Sveum said. "He's gotten quality at-bats and doing a good job. They're going to share time in the long run."
Soto was batting .191 overall, but .267 in his last eight games.
Clevenger subbed at third base on Tuesday for the first time in the big leagues. He also has filled in at first.
"He brings a lot with that bat, and I think he's only going to get better and better as he sees more and more big league pitching," Sveum said.
Ryan Dempster, scheduled to start Friday against the Cardinals, is the sixth pitcher since 1900 to win five straight starts in one season and not give up a run in those games. He joins Doc White (1904 White Sox), Don Drysdale (six straight starts for the 1968 Dodgers), Bob Gibson (1968 Cardinals), Orel Hershiser (1988 Dodgers) and Brandon Webb (2007 D-backs).
Jorge Soler, the Cuban outfielder who signed a nine-year, $30 million deal with the Cubs earlier this month, will make his pro debut in an Arizona Rookie League game on Thursday. Soler was expected to be the designated hitter for the Mesa Cubs.
Albert Almora, the Cubs' No. 1 Draft pick, also has been working out in Mesa, but has yet to get into a game.
Pitcher Randy Wells, who was 1-2 in 12 games, including four starts, with the Cubs, then designated for assignment in June and outrighted to Triple-A Iowa, has been placed on the disabled list with a right elbow strain.