DENVER -- Alfonso Soriano joked that he had not seen Starlin Castro go 0-for-4 before, which the young shortstop did Friday against the Rockies.

"I said, 'You'll get four hits today,'" Soriano said. "He goes 0-for-4 [Friday], and the next day he gets four hits. He doesn't get down. I think he thinks, 'OK, I went 0-for-4, I'm going to be a strong man and get more hits.'"

The youngest player in the Major Leagues, Castro is leading the Majors in hits with 28 after another multihit game in the Cubs' 9-5 loss to the Rockies on Sunday. He matched his personal high with a four-hit game on Saturday.

"I love what he's doing and am enjoying it while he's doing it," Cubs manager Mike Quade said.

Soriano deserves an assist. Castro and Soriano stick to their pregame routine religiously and go to the batting cage together for sessions with hitting coach Rudy Jaramillo.

"That's the only way you can get better is working," Soriano said. "He's good, but if he doesn't work, he'll just stay good. He won't get better."

Last May 7, Castro was promoted from Double-A to the big leagues. He's still got work to do. The Cubs would still like to see more plate discipline, but not if it takes away from his effectiveness. He's batting .418. Why mess with that?

"I think he'll be even better if he can learn to lay off some of those pitches," Quade said. "Maybe he never does that and he becomes a fabulous hitter who has a large strike zone. He understands. He's pretty good [with pitches] down, especially before he gets two strikes. There's areas of discipline that he shows you, but once he gets two strikes, he does expand and it's amazing.

"He doesn't swing and miss very often. If he can reach it, he usually gets a piece of it."

Castro also has thrived at the top of the lineup. He's 18-for-32 (.563) and has scored eight runs in seven games as the leadoff man.

"I can stay in the leadoff spot," Castro said after Sunday's game, in which he had two singles, an RBI double, a walk and scored two runs. Quade gave Castro the green light on a 3-0 count in the fourth, and the kid delivered with his two-out RBI double.

"I'm working harder at being more disciplined and taking more pitches and taking a walk," Castro said. "The leadoff hitter has to score a lot. I'm seeing the ball pretty good, I'm swinging at strikes."

"I'm so proud of him," Soriano said. "He's 21 years old. What he did last year surprised me. What he's doing so far [this year] is also a surprise."

Castro has also been able to handle more interviews in English. He's working on it.

"He's a little shy with the media," Soriano said. "He likes to talk, but in English, he's a little shy."

Give him time, and Castro will figure it out.

"His talent is obvious," Quade said. "I'll be real anxious to see where he's at in a couple years."

Russell likely starter for Cubs on Tuesday

DENVER -- James Russell is still on track to make his second big league start Tuesday when the Cubs play host to the Padres. Maybe.

Cubs manager Mike Quade said that might change if they needed Russell on Sunday in relief, which they didn't. The lefty pitched in two games against the Rockies this weekend, throwing seven pitches on Friday and two on Saturday.

In his only start last Tuesday in Houston, Russell threw 55 pitches but couldn't finish two innings. The only thing certain is that the Cubs will stay in-house.

"It's who's available, who's pitching well, who's stretched out," Quade said of his choices. "Just weighing all the options, we feel in-house is the best option."

The rotation after the Cubs' series against the Padres also is still to be determined. The team had talked about keeping Ryan Dempster on a five-day schedule, but with an off-day Thursday, that would mean Casey Coleman would have seven days between starts.

"Right now, this early in the season, Demp was fine with an extra day," Quade said. "That will be an as-we-go situation."

Coleman picked up the win Saturday against the Rockies, going 5 2/3 innings. He did take a liner off the top of his right foot but was fine on Sunday. Because of the way he ties his shoes, the ball hit an area that has extra cushion due to the shoelaces.

"I can't even tell I got hit," Coleman said.

Cashner, Wells to be examined Monday

DENVER -- Cubs pitchers Andrew Cashner and Randy Wells, both on the disabled list with shoulder and forearm problems, respectively, will be examined on Monday in Chicago to update their progress.

Both were scheduled to see team orthopedic specialist Stephen Gryzlo.

Neither pitcher has any pain or discomfort. Cashner, who has a strained right rotator cuff, and Wells, who has a strained right forearm, were placed on the disabled list April 7 and told they could not pick up a baseball for two weeks.

"I've picked one up," Wells said Sunday. "I haven't thrown one."

The exam Monday will help gauge where the two right-handers are at with their rehab.

Extra bases

• Alfonso Soriano leads the Cubs with five home runs after 15 games. Last year, he didn't hit his fifth until May 2 in his 24th game of the year. The difference? He's healthy. "Every year, my goal is to stay healthy," Soriano said. "If I'm healthy, I'll produce more. If I can't play 100 percent, I'm not the same player."

• Jeff Baker may be getting more work in the outfield to get his bat in the lineup. Baker played four games in right field last season for the Cubs. "If he can play a little outfield, that's not a bad option," manager Mike Quade said.

• John Grabow faced four batters last Monday in Houston and had no problems. But in his last two outings, he's given up six runs and six hits, and on Saturday, he walked three. "He's just been a little inconsistent right now," Quade said. "We're a .500 club right now because we've had inconsistencies throughout the year. With relievers especially it can be from outing to outing. If I see three, four outings like that, it can be a concern."

• What were Quade and home-plate umpire Bob Davidson discussing in the eighth inning on Sunday? "I don't know what he was yelling at me for," Quade said. "There was some growling on the first pitch to [Geovany] Soto, and it got a little louder than Bob wanted." The first pitch to Soto was a called strike.