"I think that, at times, anyone can be in some form of denial," Girardi said. "What he tells you and what he says to us might be two different things. I think players are positive people and they're confident people.
"But there is no doubt about it: Joba needs to pitch better. And he knows that. He'll be the first one to tell you he knows that."
Chamberlain allowed six hits and three walks, including a three-run homer to Ken Griffey Jr. Chamberlain speculated that if "you take away two pitches, maybe it's one or two runs," but Girardi said that the Yankees needed to see an effort more like the one the right-hander turned in on Sept. 14 against the Angels at home.
"One or two bad pitches usually doesn't lead to seven runs unless there's some errors or funny things that happen," Girardi said. "That was not the game he's capable of pitching. He pitched much better against Anaheim on Monday. And we need him to pitch much better this weekend."
Chamberlain's next start is set for Saturday against the Red Sox at Yankee Stadium, where the right-hander will get an opportunity to bust a slide that has seen him go 0-4 with an 8.42 ERA in his past eight starts as the Yankees revamped the "Joba Rules" to keep his innings in check.
"It's going to take a lot more than this to get me down or beat myself up," Chamberlain said on Sunday. "I know I've still got a lot of work to do, and we've got a long way to go. I've just got to get back out there."
Chamberlain had been scheduled to throw 85 pitches against the Mariners on Sunday but fired just 69 before being lifted due to ineffectiveness. Girardi said that he still sees Chamberlain as a potential starter in the playoffs, but he mentioned that Chad Gaudin will have an opportunity to work his way into consideration.
Since the Yankees appear likely to select the "A" schedule for the American League Division Series, they could avoid using a fourth starter for the first round of the playoffs, needing only CC Sabathia, A.J. Burnett and Andy Pettitte. But if the club is to accomplish all of its objectives, it should have an effective Chamberlain ready when duty calls.
"Obviously, we need him to pitch well," Girardi said. "He's important for our success. It's time for him to step up, and he needs to step it up."