"I'm hoping to write a big check next year, so the pressure is on," Udine said.
There were plenty of people wearing Cubs jerseys in the crowd. Dawson, who played for the Cubs from 1987-92 and is now in the Marlins front office, lives in the Miami area, and drove up to attend the event.
"When I first saw [Rizzo], I was in awe of how big he is," Dawson said. "He's a gem. I like what I see and he'll do real well."
Even Oakland outfielder Yoenis Cespedes, who lives in the area, turned out on the sunny day.
"I've been seeing a lot of new faces and old faces who have supported me," Rizzo said. "It's really awesome to see the turnout."
Rizzo, 23, lost his grandmother to cancer, and ever since he's been motivated to fight back. His mother, Laurie, coordinated the walk, and her son got choked up thanking her.
"This foundation, it means a lot to me because it's a family foundation," Anthony Rizzo said. "The family really helped out.
"Beating cancer and overcoming everything -- it's all hitting me right now," he said, pausing to collect himself. "It's crazy -- I'm usually never like this."
The crowd responded with cheers.
"There are people here who he's known since he was little," Laurie Rizzo said.
Including a former assistant Little League coach who remembered when young Anthony launched a ball well over the fences.
"There wasn't another kid on the team who could hit the ball half as far," the coach said.
The walk, which raised more than $63,000 online prior to Sunday's registration, is just the first step for Rizzo.
"We just want to build on this," Rizzo said of his foundation. "Kerry [Wood] and [Ryan] Dempster, they've set the bar with their foundations in Chicago."
Former Cubs pitchers Wood and Dempster both have family foundations that have been very active. For now, Rizzo is doing his part in his hometown. Proceeds will benefit the Sylvester Comprehensive Cancer Center, part of the University of Miami health system, as well as Livestrong, which both helped Rizzo through his ordeal.
"Growing up here, and everyone coming out and supporting me, it was really cool," Rizzo said.