CHICAGO -- Fourteen of Alfonso Soriano's 15 home runs this season have been solo shots, but don't expect the Cubs to move him out of the leadoff spot in the order to get more RBIs.

Soriano prefers leading off, and that's where the Cubs will keep him. The Washington Nationals did move him to third in the order in the last month of the season in 2006, but that was because they wanted to give him the chance to total 100 RBIs. Soriano finished with 95.

"I think I can use my power and speed batting leadoff," Soriano said Monday.

The Cubs left fielder was named last week's National League Player of the Week.

He led the National League with four home runs and a slugging percentage of 1.080. Soriano led the NL with 27 total bases and tied for first with 12 hits last week as well as posted a .480 batting average, which was second in the NL for the week. The five-time All-Star drove in five runs, scored six, and homered in three consecutive games against the White Sox.

"He should be [Player of the Week] -- he had a heck of a week," Cubs manager Lou Piniella said of Soriano.

He's having a great month, batting .350 so far in June compared to his .270 April and .302 May.

"It was just a matter of time," Chicago's Mark DeRosa said.

"The warmer weather has helped, I think the move to left field has helped," Piniella said. "The fact that he's acclimated to day-night games has helped. Truthfully, having [Felix] Pie here -- they seem to have a nice rapport going.

"And the last reason is he's a very talented young man who's finally hitting his stride," Piniella said.

Soriano has taken advantage of pitchers, slugging leadoff homers before most of the fans are settled in their seats. Pitchers know he's a fastball hitter, and still throw fastballs.

"The first pitch of the game, that's the best pitch the pitcher has to open the game," Soriano said. "It's a little complicated because they know I'm a fastball hitter but they don't want to throw a first pitch breaking ball because they don't feel comfortable. I always feel good swinging at the first pitch."

But Soriano is more proud of his defense. He is tied for first in the National League with nine outfield assists.

"I'm very proud of my defense, better than the hitting," Soriano said. "I think that's the only problem I have. When I came to the league, everybody talked about how I'm a very good offensive player. I'm very proud of what I do in the outfield now."

Stalled: The Cubs did not make a roster move Monday night, and opted to go with 11 pitchers, although in reality it's only 10. Ryan Dempster was not available and the bullpen was short-handed.

"I would think by [Tuesday] we'll have one here," said Piniella, who would prefer 12 pitchers on the roster.

Dempster felt better, and threw off flat ground on Monday. He'll throw off the mound on Tuesday and how he feels after that will determine whether the Cubs need to place him on the disabled list.

The corresponding roster move will be tricky if the Cubs chose to add another pitcher. Someone has to go from the 25-man roster. It won't be Pie, Piniella said.

"I'm just giving him a day or two to catch his breath," Piniella said of the rookie, who was 2-for-19 in the last six games, and batting .227 overall. "You'll see him out there in center field [on Tuesday night].

"We're teetering -- we do need a pitcher," Piniella said. "But Pie's not going anywhere."

DeRosa made his fourth start in right field Monday night. Aramis Ramirez was back at third base, and Piniella likes Mike Fontenot at second.

"We can move [DeRosa] around a little bit," Piniella said. "He can play the outfield, play second. When I give [Ramirez] a break at third base, he can play third. He's very valuable in that role."

Fontenot did take grounders at shortstop on Monday, and might be an option there.

Extra bases: The Cubs finished with the best Interleague record in the National League at 8-4. ... Kerry Wood is with the Cubs during this homestand. Piniella saw Wood in the dugout and asked the right-hander if he was going to throw off the mound. "No comment," Wood said. ... A clarification: Juan Uribe was charged with obstruction in the eighth inning of Sunday's game between the Cubs and White Sox, not interference. Defensive players are charged with obstruction, offensive players are charged with interference.

Minor matters: Sean Gallagher threw five scoreless innings, giving up one hit and walking two, in Iowa's 4-3 win over Albuquerque. It was Gallagher's first start for the Iowa team. Geovany Soto, Buck Coats and Ronny Cedeno each homered. ... Justin Berg gave up one run on six hits over 7 1/3 innings in Tennessee's 4-1 win over Carolina. Matt Craig hit a two-run homer. ... Jeff Samardzija gave up five runs on eight hits over five innings in Daytona's 7-6, 11-inning loss to Tampa. Brian Dopirak hit a home run and a RBI double. ... Jose Pina gave up five runs on five hits over 5 1/3 innings in Peoria's 11-9 win over Beloit. ... Boise remained winless, losing 5-4 to Eugene. ... Elvis Lara homered in the Mesa Cubs' 11-6 win over the Giants.

Also, Tennessee's Mark Holliman was named Southern League Pitcher of the Week. He threw a seven-inning no-hitter on June 21 against Huntsville. In the game, the right-hander gave up one walk and struck out three. Holliman, 23, is the first Smokies player to throw a no-no since Leo Estrella did so May 27, 2000. Holliman helped himself by hitting a two-run homer in the game.

It's the second time Holliman has won the honor this year. He also was named the league's Pitcher of the Week for April 16-22.

On deck: Left-hander Ted Lilly will start the second game of this three-game series against the Colorado Rockies. First pitch is scheduled for 7:05 p.m. CT, and the game will be broadcast on WGN.