And he apparently did it all even though the vision in his right eye was blurry.
Zambrano is to see an eye doctor on Saturday and is expected to have LASIK surgery performed on the eye before Spring Training starts.
"My eyes have been bothering me for a while," Zambrano said on Friday, during the first day of the Cubs Convention. "I have to take care of that -- I have to see the strike zone good. It's part of my job."
He had contacts, but he didn't like putting them in his eyes. Glasses?
"I don't like glasses," he said.
The problem began last season, but it didn't seem to affect the right-hander on Sept. 14, when he threw a no-hitter against the Houston Astros in a game played at Miller Park. He said the surgery should help.
"I can throw more strikes," he said.
The question remains: How has he been able to do so well at the plate if his vision is fuzzy?
"I just close my eyes and see the ball," he said, smiling.
He's done pretty well. Last year he had a hit in 13 straight starts.
"I'm not blind," he said. "I have good vision. But there's something wrong with my eye that has to be corrected."
The Cubs have been monitoring Zambrano's right shoulder this offseason, and they sent trainer Bob Grimes to Venezuela twice to check on the pitcher's strength and flexibility. Grimes and Zambrano's personal trainer, Frankie Alvarez, will make one more trip before Spring Training starts.
Zambrano said that he has already thrown two bullpen sessions since Jan. 1. He's ready.
"Whatever happened last year is in the past," he said. "I have to work hard and keep myself in shape and do a good job."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.