Nationals manager Davey Johnson heard about Yocum's death Monday night.
"He's a legend," Johnson said. "I mean, doctors are such a big part [of the game] ... I don't think anybody in baseball has passed through without going to, being in front of Yocum or [Robert] Kerlan or [Frank] Jobe, [James] Andrews. They're just as much a part of the game as the players. They keep us on the field."
Zimmermann didn't know about Yocum's illness until this weekend. When he found out about it, Zimmermann sent Yocum a text message telling him to get well soon.
"I didn't know how bad it really was until 10 minutes ago," he said before batting practice Tuesday. "He saved a lot of guys' careers, he fixed a lot of guys and did a lot for the game of baseball.
"Obviously, he saved my career and I wouldn't be here without him."
Espinosa tore the rotator cuff in his left shoulder in September but wasn't initially aware of the tear. He sought a second opinion from Yocum after the season.
"It's tough to hear [about] his passing," said Espinosa, adding that Yocum also performed elbow surgery on his brother, Brandon. "He helped me out, he got me right, got me to his best physical therapist, and they got me in a position where he could get me going. It's definitely sad and it's a big loss for the baseball world."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also could be found on Twitter @WashingNats. Tom Schad is an associate reporter for MLB.com. Follow him on Twitter @Tom_Schad. This story was not subject to the approval of Major League Baseball or its clubs.