"I'm going to fight it and deal with it," said Gardenhire, who was set to begin his first season in Arizona after the team hired him this past November. "It's a bump in the road, and it's not how I envisioned starting Spring Training with a brand-new team. It's part of life.
"With the backing of this ballclub, we'll get through it, and I'll get through it."
Gardenhire is a former American League Manager of the Year Award winner who skippered the Twins to a 1,068-1,039 record and six postseason appearances from 2002-14. Previously, Gardenhire spent 11 seasons as Minnesota's third-base coach, including the team's second World Series championship in 1991, after a five-year big league career with the Mets from 1981-85.
The D-backs' coaching and front office staff voiced their support for Gardenhire as part of a team statement.
"We are a family," said D-backs manager Torey Lovullo. "As a family, there's a series of tests that are going to come upon us, and this is a big one, but we're going to come together and help Gardy through this to the best of our ability."
Added general manager Mike Hazen: "It says a lot about Gardy that his first thought when he told us about his diagnosis was that he didn't want to be a distraction to the team. We are all behind him and, of course, our first concern is with getting him healthy and tackling this the way he plans to -- head on."
Matt Kelly is a reporter for MLB.com based in New York. Follow him on Twitter at @mattkellyMLB. This story was not subject to the approval of Major League Baseball or its clubs.