"For me, it made too much sense," said Roberts, who has been cancer-free since late in 2010 after being diagnosed with Hodgkin's lymphoma earlier that year.
Now, Roberts and the Padres -- the first Major League team to partner with Stand Up To Cancer -- are donating a 60-minute private baserunning and fielding lesson with Roberts at Petco Park.
The winner will also receive four game tickets.
"I'm excited to be a part of it," said Roberts, who has been the team's first-base coach since 2011.
The Winter Meetings, which began on Monday, are featuring the MLB.com Auction to benefit Stand Up To Cancer, which MLB has supported since 2008 as founding sponsor.
Public relations representatives from all 30 clubs were inspired to act based on individual club members affected by the disease, and jointly organized the auction and announced it on Monday in Nashville with MLB staff.
The bidding closes at 8:59 p.m. PT on Thursday for more than 70 baseball-related experiences ranging from clubhouse tours by players to lunches with general managers to team bus rides to meet-and-greets with 14 Hall of Famers.
In 2010, their first year partnering with Stand Up To Cancer, the Padres raised nearly $318,000 as part of the initiative created to accelerate groundbreaking cancer research.
The organization has been touched by cancer in recent years, first with Roberts. Bullpen coach Darrel Akerfelds died last summer after battling pancreatic cancer. Hall of Fame outfielder and part-time television analyst Tony Gwynn underwent surgery for cancer of the parotid gland.
Roberts has been very encouraged by baseball's role in the Stand Up To Cancer initiative and for the Padres' leading role in that.
"It's great to see people from baseball and the entertainment industry sort of crossing lines to raise money," Roberts said. "And for me to be a part of it says a lot about our organization."
Roberts first felt a lump on his neck during Spring Training in 2010. He was diagnosed with Hodgkin's lymphoma, a cancer of the lymphatic system, which is part of the immune system.
He underwent chemotherapy twice a month for four months and had radiation treatment every day for three and a half weeks. He now gets a checkup once a year, and said he's never felt better.