MILWAUKEE -- The Cubs will take advantage of Interleague Play in an American League ballpark and use Alfonso Soriano as the designated hitter, giving him three days off a sore left knee.

"It's coming right at the right time," manager Dale Sveum said of the three-game series against the Twins, which starts on Friday. "I've been playing [Soriano] every day. He's that one threat in our lineup, and it's hard to give him days off at all. To his credit, he doesn't want any days off, and he doesn't take days off from work. You have to give him credit for that."

Soriano entered Thursday's game with nine home runs in his last 21 games, dating back to May 15, more than any other player in the Major Leagues since that time. His left knee is tender, but it hasn't limited him at the plate. It does make it difficult for Soriano to stop in the field when he's chasing balls.

Soriano has started 52 of the Cubs' 57 games in left. He's impressed Sveum with his pregame preparation as well as his attitude during batting practice.

"He's not taking any days off in the outfield and working," Sveum said. "That's the most impressive thing of all. ... I have tons of admiration for Soriano. He's been far and above anything I've expected."

Castillo to start rehab; Soto could follow soon

MILWAUKEE -- Catcher Welington Castillo will begin a rehab assignment on Friday with Double-A Tennessee, while Geovany Soto will continue his rehab work with the Cubs and could possibly be assigned next week.

"They're still struggling a little on blocking," manager Dale Sveum said. "Everything seems to be right on schedule except pushing off to their left to block balls."

Soto underwent arthroscopic surgery on his left knee on May 17; Castillo is on the disabled list with a sprained right knee and has been sidelined since May 19.

Sveum, Cubs eager for Target Field visit

MILWAUKEE -- This weekend, the Cubs get their first look at the Twins' new home, Target Field.

"It's a fantastic stadium," said manager Dale Sveum, who has been at the ballpark for Interleague games between the Twins and Brewers. "It's probably one of the best venues there is as far as atmosphere. They built a unique stadium. It plays a little big sometimes, but when the weather is warm, it plays a lot different."

Outfielder David DeJesus played there during his days in the American League.

"The guys will be impressed going from the Metrodome to this field," DeJesus said. "It's awesome."

Is it pitcher-friendly?

"Definitely," DeJesus said. "In the middle of the field, it's pretty deep. Down the right-field line, the high wall, it's not as deep, and in left field, the ball carries pretty good. It plays true to what it is."

OK, let's ask a pitcher who has played at Target Field.

"I'd say it's fair," reliever Shawn Camp said. "It's definitely hitter-friendly down the lines. It's less hitter-friendly than most parks. The alleys are deep."

Neither DeJesus nor Camp miss the Metrodome. Camp said that his team was once forced to play a 9 a.m. game to accommodate a University of Minnesota football game, and DeJesus lost a fly ball against the domed stadium's roof.

"But at least it went foul," DeJesus said. "I was running to the line, and next thing you know, I was looking up and it was out near the bullpen."

Extra bases

• The Cubs reached double-digit strikeouts on Tuesday and Wednesday against the Brewers, fanning 14 times in the first game and 15 in the second. It's the first time since May 30 (14) and May 31 (23) of 2003 that the team reached at least 14 in back-to-back games. The May 31 game went 16 innings.

"Most strikeouts are going to be away and soft, and we've got to really start grinding a little more and take that part of the plate away from people," manager Dale Sveum said.