"He looked me in the eye and he swears that he's going to be back, as good as ever," Cashman said. "It's up to us to buy into that or not."
Posada's season ended in late July with arthroscopic surgery on his throwing shoulder, which curtailed his ability to gun down runners and relegated him to duty as a first baseman and designated hitter at times.
Cashman said that he does not plan to pursue a free-agent catcher as of now -- Ivan Rodriguez, who was acquired in July from Detroit, is one -- but that could change depending on how Posada gets through his rehab. Posada is set to begin a throwing program on Dec. 1.
"The preference for me would be if Jorge Posada can catch and return to norm," Cashman said. "That's where we're strongest. He was a huge loss for us. He was a catcher that obviously provided defense.
"But his offense was so significant and was such a difference maker for this franchise for so long that when we rolled the balls out there every day, we had a distinct advantage."
The Yankees have a pair of veteran starting pitchers set for free agency in Andy Pettitte and Mike Mussina, both of whom are mulling retirement on some level. Jason Giambi, Bobby Abreu and Carl Pavano are also among the team's notable free agents, and the Yankees will not bring all -- or even necessarily any -- of them back.
"In some of these cases, some of these guys are going to go without having the chance to win a world championship," Cashman said.
Manager Joe Girardi said that his gut instinct is that Pettitte will continue to pitch, and he only wishes to pitch for the Yankees. But Girardi is not so sure about Mussina, who could walk away after recording the first 20-win season of his career.
Cashman said that retirement is "something that's weighing on [Mussina's] mind," but it is "certainly possible." The Yankees could reach out to him if their plans to address the starting rotation via free agency or trades do not pan out.
Hank Steinbrenner has already targeted CC Sabathia and A.J. Burnett as potential options, and one offseason after the Yankees turned down a chance to trade for Johan Santana, Cashman hinted the process of developing talent may be more ripe.
"I'm not afraid to pursue big players, I'm not," Cashman said. "It's not something I'm against. I'm not trying to change that side of it. There's a time and place when you push that button.
"This past winter, I didn't feel the building process was enough completed to start jettisoning off. When you make a big play like that, you've got to get where you need to be. That's like the finishing piece."
With Giambi up for free agency, several players have lobbied to play first base for at least a portion of the season, including Johnny Damon and Hideki Matsui.
Cashman said that playing either out of position is not something he gravitates toward -- Cashman prefers the idea of Matsui as a DH and likes the range Damon offers in the outfield.
"I'd like to put a first baseman at first, rather than have somebody who's trying to step up on behalf of the team," Cashman said.
Of Giambi and Abreu, Cashman said, "They happen to be the most selective hitters that we've got. This year's team, overall ... we were more of a free-swinging unit than we had been in the past. Obviously, the free agency of Giambi and Abreu is a concern to that area of weakness."
Cashman said that closer Mariano Rivera is scheduled to have surgery on his right shoulder on Monday at the Hospital for Special Surgery in New York. Dr. David Altchek will perform the procedure. He also said that the Yankees will also discuss coaching staff decisions shortly, but no concrete plans had yet been made.