Rivera is recovering from surgery to repair a tear in his right anterior cruciate ligament suffered in a batting practice mishap on May 3 in Kansas City.
Rivera has signed a one-year, $10 million contract to continue his career. He expects to feel 100 percent soon, but the game's all-time saves leader with 608, plus 42 more in the postseason, isn't quite there yet.
"I don't want to give you a number, I don't want to speculate, but I'm feeling good," Rivera said. "The leg is getting stronger and stronger, and that's it. You have to give it time. I am doing my part, and time is doing its part."
Rivera recently took part in a commercial shoot that had him lob pitches off a mound, but he said that he hasn't seriously started throwing yet.
"My arm is good. Everything else feels good," he said, "so I will start throwing the baseball pretty soon."
Rivera said that he hasn't kept close tabs on the Yankees' offseason to date, but he applauded the pending moves to put infielder Kevin Youkilis and outfielder Ichiro Suzuki in pinstripes next year.
"Once the season is over, I don't follow baseball," Rivera said. "I know they're about to sign Youkilis and Ichiro; that I know because I just heard it here. Those two guys are veterans. They are good players and they know the league. They will be helpful for the team."
Many Yankees fans seemed to show mixed reactions to the acquisition of Youkilis, 34, who will take over at third base with a one-year, $12 million contract. Rivera said that some residual effect of Youkilis' years in Boston was to be expected.
"One thing I know, the guy plays hard," Rivera said. "Definitely, the Yankees [fans] won't like him because he was wearing the Red Sox uniform. I don't see why not. I can't decide for them, but he will be my teammate and I have to respect that."
Youkilis had several run-ins with the Yankees over the years, including incidents with pitcher Joba Chamberlain.
The New York Post reported on Wednesday that Chamberlain left Youkilis a voicemail in an attempt to smooth over their past, and Rivera said that Youkilis' work ethic should fit in with the Yanks.
"Again, all these years that we competed against [him], the guy always gives you the best," Rivera said. "And that's what you want for any player -- just give you the best."