CHICAGO -- Being on the losing end of Tom Glavine's 300th career victory didn't hurt the Cubs as badly as seeing Alfonso Soriano limp off the field on Sunday night. The Cubs' outfielder will be sidelined at least two weeks, and possibly a month.

"You can't replace a guy like Alfonso Soriano," Chicago's Derrek Lee said.

Glavine and the New York Mets beat the Cubs, 8-3, but the loss could be more costly than just in the standings. Soriano, the Cubs' $136 million outfielder, strained his right quad in the third inning, and underwent an MRI.

"He's not going to be out there any time soon," Cubs manager Lou Piniella said. "It's probably going to be a minimum of two weeks and probably as long as a month."

The Cubs have avoided serious injuries so far to key players. Soriano singled with two outs in the third, the first hit off Glavine (10-6). Ryan Theriot then singled to center, and Soriano took off. About four steps after rounding second base, Soriano pulled up and tried to hop to third on his left leg. The 41,599 at Wrigley Field were silent as Soriano was helped off the field.

"He's the leadoff hitter, a valuable guy, leading the team in home runs," Piniella said. "He's got a lot of energy. It's going to be a tough loss. We just have to tough it out now."

The mood changed dramatically when Kerry Wood came on in relief for the Cubs in the seventh. It was his first big-league game since June 2006, and flashbulbs popped for each of his pitches. Sidelined because of problems with his right shoulder, Wood faced four batters, and threw 14 pitches, eight for strikes.

"It's kind of difficult to talk about me after what happened with the game and with Soriano," Wood said. "I'm glad to be back out there. What happened with Soriano is our main concern right now."

Still, the reception was appreciated.

"Obviously, I would've liked to have been in a winning ballgame," Wood said. "The fans are great, and the adrenaline was going a little bit. It felt good."

He isn't thinking about his shoulder with every pitch.

"I'm just tyring to get guys out," Wood said. "I've been through this enough to know you can't go out there and worry about how you feel or if something is going to happen. You come into the game and try to get guys out and do the best you can."

The Cubs couldn't muster much against Glavine, the second pitcher to win his 300th game against the team in franchise history, joining Warren Spahn, who did so Aug. 11, 1961, in Milwaukee. However, Glavine is the first to notch the milestone at Wrigley. Both Roger Clemens and Greg Maddux were the most recent members of the 300 club who didn't succeed in their bids to win No. 300 here. The Cubs weren't interested in history.

"It's just a game for us," Piniella said. "Whether he's going for 100, 200 or 300, we have to beat him."

Glavine was a former teammate of Chicago's Jason Marquis, Mark DeRosa, and Cliff Floyd. None got a break. The Cubs mustered two runs on six hits and one walk over 6 1/3 innings. Glavine struck out one, and helped himself with a RBI single in the second.

"Typical Tom Glavine outing today," DeRosa said. "The home-plate umpire was giving him a little bit of the outside corner and he kept pumping. My hat's off to him. He's a great guy. I'm obviously happy for him, but not at the expense of us losing the game, and potentially one of our best players."

"Typical Glavine," Chicago's Jason Kendall said. "I've faced him seven times, and he gets you out in front and rolling over. He pitched a good game. I wish he didn't get his 300th against us, but he's to be congratulated. Tip your hat to him -- it's something special."

Glavine had fallen short in his first bid for No. 300 in Milwaukee five days ago when the bullpen blew a lead. The Cubs threatened to do the same. Trailing 5-1 with one out in the seventh, Angel Pagan doubled to chase Glavine. Kendall singled off Guillermo Mota, and Pagan scored on pinch-hitter Jacque Jones' groundout off Pedro Feliciano. Mike Fontenot then hit a RBI double to make it 5-3.

But the Mets added a RBI double by Carlos Delgado in the eighth, his second of the game, and a RBI single by Paul LoDuca. Delgado finished with three RBIs.

"He worked that outside corner and kept the ball down," Lee said of Glavine. "It's a battle every time you face him."

Marquis (8-7) struggled from the beginning, and gave up four runs, nine hits and two walks over 5 1/3 innings. He's now 3-6 in his last 16 starts.

"He got behind," Kendall said. "He'll be all right. You have nights like that. You have to keep going."

With the loss, the Cubs remained one game behind the Milwaukee Brewers in the Central. Before the game, some of the Cubs players watched the final innings of the Brewers' 8-6, 11-inning loss to Philadelphia. The players may say it's early, but judging from the cheers, there were a lot of Phillies fans in the Cubs clubhouse on Sunday. The Cubs finished the homestand 3-4.

"Milwaukee gave us a chance to pick up a game and we didn't do it," DeRosa said. "We're frustrated -- I think more frustrated about the loss of Soriano tonight. You're not going to win every ballgame. We ran into a good team, a hot team right now, a first-place team and played them tough. When you lose your catalyst and the pulse of our team, it'll be tough to swallow."