Manager Joe Girardi acknowledged the news conference but declined to divulge the topic, saying that the person holding it should be the one to divulge the topic. Nonetheless, he certainly didn't deny the reports that it would center on Rivera.
"Greatest closer of all time," Girardi said when asked his thoughts on Rivera. "No question in my mind. I've had the thrill of catching him, and I was there when he really burst onto the scene and was a dominant setup man. To see what he's done as a closer has been a thrill for me. I know there's a press conference on Saturday and we'll go from there."
ESPN.com and the New York Post are among the outlets reporting that Rivera will announce the end of a career that has spanned 18 seasons, all of them with New York.
Rivera strongly indicated, but never officially announced, that the 2012 season would be his last in the Major Leagues. However, he suffered a major knee injury in May and missed the remainder of the season. Following that, he elected to come back for 2013.
Rivera is the all-time Major League leader with 608 saves, and has a 2.21 ERA in 1219 2/3 big league innings. He is also one of the greatest postseason pitchers of all time, with a lifetime 0.70 playoff ERA and 42 saves in 96 appearances. He has been a part of seven pennant winners and five World Series champions. And he did it all leaning primarily on one pitch, a wicked cut fastball that bores in on the hands of left-handed hitters and away from righties.
"A lot of pitchers throw cutters," Yankees outfielder Ichiro Suzuki said through a translator. "You go up there waiting for the cutter and you can't hit it. You can't even compare what other guys throw compared to his cutter, because when you go up there and think he's going to throw me a cutter and waiting for it, but you still can't hit it. ... Pitchers obviously try to throw to places that hitters will have a hard time hitting, placing the ball where a hitter doesn't want to have it thrown at, but Mariano would just throw to where you are waiting for the pitch and you still can't hit it."
Beyond his performance, Rivera has also been revered for his personality.
"Mariano's a great person," said starter Ivan Nova. "He's a great person, a great teammate, and he was the one who was on top of me in 2011, pushing me, pushing me, pushing me all the time. And one thing that he told me when I saw him this year was that he was going to be on top of me. ... When a veteran like that motivates you that way, it means a lot."