"I'm not happy with it," said Posada, who was told he was being benched before Sunday night's game against the Boston Red Sox. "I don't need to tell you again that I'm not happy with it. But I'm moving on, and I'll be ready to play whenever I happen to play.
"Whenever I get a chance to play, I'll be ready to play and get the most out of it."
Girardi approached Posada in a pregame meeting to give him the bad news.
"He said he's going to put the best lineup on the field, and he doesn't know when I'm going to DH again, so right now I'm sitting (on) the bench," Posada said Sunday.
"No," Posada replied Tuesday when asked if he had a chance to plead his case. "I can't do anything about it. We talked about it on Sunday, he told me what he felt and that was it. I just gotta go out there and play whenever they give me a chance.
"I can't control not being in the lineup. Like I said, I'll be ready when they put me in there."
Asked if his role had been defined going forward, Posada said, "I'm on the bench."
At the time of his benching, Posada was hitting just .230 with nine home runs and 31 RBIs. Since the All-Star break -- a span of 17 games -- he's hitting just .232 with two RBIs.
Posada said he "felt good" at the plate last week in Chicago, and thought "good things were about to happen."
But in the month of August, he's had just three hits in 18 at-bats. And that prompted Girardi to make a change.
Ironically, it was Posada that took Girardi's starting catching job with the Yankees in 1998.
"I didn't like it (when I was a player)," Girardi said. "I just kept working at it and trying to get better. As a player, that's the only thing you can do. Be prepared, and when you get your chance, perform and be prepared."
The 39-year-old Posada is in the final year of his contract, and it appears unlikely he'd return to the team next season -- if he makes it through the end of this season. In 2011, his first year as a full-time DH, Posada, a switch-hitter, was hitting just .103 against left-handed pitching (6-for-58) as a right-handed batter. His last homer came on June 29.
Posada's demise began on May 14, when he and his .165 batting average were dropped to ninth in the batting order against the Red Sox. He then removed himself from the lineup, promptly drawing heavy criticism for the move.
Posada seemed to have righted his ship at the plate after that, hitting .326 in his next 31 games, which brought his average up to a season-high .240.
But he's hit just .205 with four RBIs in 78 at-bats since July 1, and has become a liability to the Yankees rather than an asset.
Eric Chavez was in the lineup as the team's DH for Tuesday night's 6-4 loss after starting there on Sunday.
The Yankees are also contemplating calling up top prospect Jesus Montero, who could receive some at-bats at DH against left-handed pitching.
Mike Mazzeo is a regular contributor to ESPNNewYork.com.