The so-called ace of the pitching staff gave up 11 hits and four runs (three earned) in just 3 1/3 innings during Sunday's 4-1 loss to the New York Mets at Wrigley Field. In his last three starts, Zambrano has gone no longer than 4 1/3 innings, and he has a 10.13 ERA over those three starts.
After Sunday's game, Cubs manager Lou Piniella said Zambrano is "opening up" too quickly in his delivery.
"He's opening up; his front shoulder and his arm are dragging," Piniella said. "He's going to have to work on it. They (the hitters) are getting a good look at him. They're not swinging and missing at all, which gives you a pretty good indication that you're showing the ball to the hitter a little prematurely, and it gives the hitter a longer look."
Zambrano said he spotted the flaw while watching video of the game after his short outing. He said that he and pitching coach Larry Rothschild will work on staying closed during his next bullpen session.
--RHP Ryan Dempster won his second straight start Saturday. It was the first time since last September that he recorded back-to-back wins. After winning 17 last year, Dempster is 8-7 with a 4.15 ERA.
--Zambrano has a 12.91 ERA over his last two games, both losses. The 11 hits he gave up Sunday were the most since he allowed 13 at Dodger Stadium on June 7, 2008.
BY THE NUMBERS: 1 -- RHP Carlos Marmol has had his problems with walks, but he had allowed just one home run through the weekend. That covered 60 1/3 innings and put him second in the majors to Atlanta reliever Peter Moylan in fewest homers allowed with a minimum of 50 innings pitched.
QUOTE TO NOTE: "There's nothing wrong with playing the role of a big underdog. There's nothing wrong with that. We've got to go out and play on the field regardless of what people write or don't write. The less attention, the better." -- Piniella on people writing off the Cubs for 2009.
--LF Alfonso Soriano had an MRI on his left knee Saturday, and he took a cortisone shot Sunday. The Cubs say the MRI turned up nothing more serious than inflammation. Soriano could be back in the lineup by Tuesday night. On days when Soriano has to sit, Jake Fox will get the starts in left. He hit a grand slam in Saturday's 11-4 win over the Mets.
--RF Milton Bradley raised his on-base percentage to .401 with a walk, a single and getting hit by a pitch. Bradley is 12-for-22 (.545) on the homestand, with nine runs, five walks, three doubles and two homers. His OBP is best among Cubs regulars.
--3B Aramis Ramirez extended his hitting streak to eight games, during which he's 13-for-33 (.394). Ramirez also has hit safely in 18 straight home games, dating to July 7.
Cubs left fielder Alfonso Soriano was the subject of conversation before and after Friday's 5-2…