In the Yankees' eyes, Posada remains a catcher -- but not on Sunday afternoon. With a tough left-hander on the mound for the Mets in the Subway Series finale at Shea Stadium, manager Joe Girardi elected to rest Jason Giambi and use Posada at first base, with Jose Molina catching.
"I want to catch. I'm a catcher; I'm not a first baseman," Posada said after the game. "But every once in a while, if they ask me to, I'm going to do whatever it takes to win a ballgame. For me to play first base on a day like today, I can do that."
Girardi was all too cognizant of the splits that Mets lefty Oliver Perez has compiled this season -- a .173 batting average vs. left-handed batters and a .265 vs. right-handed batters, he rattled off -- as he explained a rather unorthodox Yankees lineup that rested not only Giambi, but also Bobby Abreu and Robinson Cano.
Giambi, who came on to pinch-hit in the eighth inning on Sunday, might have served as the designated hitter if the game was played under American League rules, but to combat the left-handedness of the Yankees' lineup, switch-hitter Wilson Betemit filled in at second base and the right-handed-batting rookie Justin Christian assumed duties in right field.
Perez limited the Yankees to two runs and three hits over 7 2/3 innings on May 18, and Girardi wondered if the lineup shakeup would help combat a repeat from the perennially unpredictable Perez.
"We tried our left-right, left-right the last time against him at Yankee Stadium, and it didn't work out too well," Girardi said.
On Sunday, Perez tossed seven strong innings, striking out eight and giving up just one run -- a solo homer to Betemit in the seventh.
Posada, 36, came up as a second baseman in the Yankees' system, though he converted to catching in the low Minor Leagues. On Sunday, he grumbled when the idea of playing first base came up in periodic conversation, though such duty has not been uncommon -- he switched to first base in Saturday's game on a double switch.
"I think he has the ability to play there, because he was an infielder," Girardi said. "He moves his feet well, and I think the position comes pretty natural to him. Obviously, who knows what's going to happen in the next couple of years?
"We signed him on to be a catcher. That's what we signed him on to be. But it's nice that he's able to do more than one thing for you; obviously, you're not going to catch a guy seven, eight, nine, 10 days in a row. You can keep his bat in there and you can do some different things with him."
Having Posada at first base earlier this season was not an option because the Yankees were still cautious about his tender throwing shoulder, which has improved markedly as of late, even though the Yankees have no immediate plans to remove third catcher Chad Moeller from the roster.
That opens Posada up to additional duty; with the first pitch on Sunday, Posada will have already appeared in six games this season at first base, after having only done it four times since the beginning of the 2001 season.
That noticeable change from the Joe Torre era has not taken place by accident, Girardi said.
"I like players being flexible, where they can play more than one position," Girardi said. "To me, it makes managing easier."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.