Rivera tore the ACL in his right knee while shagging fly balls during batting practice on Thursday and is out for the season.
"Mariano, man, I always say he's the best pitcher in the game I've ever seen," David Ortiz said. "Period. Simple. One pitch."
"What do you say? I mean, he's the greatest closer ever," Hall of Fame closer Dennis Eckersley said. "That's not the way he wanted it to end. And I don't know if it is the end."
Told Rivera had announced Friday afternoon that he would indeed make a return attempt, Eckersley was glad to hear it.
"Makes sense. Makes sense," Eckersley said. "If you think about it, he can. And it gives him some incentive. He didn't want to go out like this. He won't shag anymore. I've seen a lot of guys and I've seen guys get hurt. But that's what he does. But you know, and you see the replay, it was nothing, probably compared to some of the ways.
"If it was over, it's easy for me to say, 'He never had a bad year. So he gets to walk away sort of like that. But now he can come back.'"
Ortiz and manager Bobby Valentine spoke of their reverence for Rivera before the news broke that Rivera would try to come back.
"It was sad, man," Ortiz said. "Mariano is a guy that ... good people, man. Good people. Last night when I saw it on TV, it was pretty emotional. Going out the way he did was unbelievable. He was doing what he was supposed to do. Injuring himself like that, I guess you don't expect it, but it happens. We come in early, we do our workout. If you get injured working out, doing what you're supposed to do, there's nothing you can do about it. It was pretty sad, seeing him last night going through what he went through. You don't want to see anyone getting injured, especially a guy like Mariano.
"Me and Mariano, we are really good friends. He's the kind of person that's a major believer in, God has something always planned for us. I'm pretty sure if that's the way God wants him to finish his career, he'd understand that, he'd agree with it."
Valentine, as manager of the Mets, saw up close as a younger Rivera closed out the 2000 World Series.
"I liked my closer [Armando Benitez] at the time, too, and the series kind of went because one of their batters had a great at-bat against our closer and we didn't have any great at-bats against Mariano," Valentine said. "But 2000 he was great. And we knew that. The plan was to not get him in the game, not beat him once he got in. We didn't follow the plan. Or we didn't execute the plan.
"Mariano, everybody knows, I can only be redundant in anything that I say because he's one of the greatest guys I ever met. Obviously one of the great athletes who was doing an athletic event when he got hurt. Goes without saying, the kind of pitcher he was, I don't think I'll ever see it in my lifetime again. He's special, hopefully he can come back, even though he's with the bad guys."
Valentine said the Yankees would feel Rivera's loss if their starters can't go deep into games.
"I think it'll depend on their starting pitching. If they're going to the sixth and seventh a lot, I think they're going to miss him," Valentine said. "If their starting pitching stretches out into the eighth inning, they might be OK. [It's] still not going to be as comfortable a feeling, for sure."