"With the Cubs-Cards series, it was one of those things where it was the perfect chance to do it," said Motte, who was drafted by the Cardinals in 2003 and played for St. Louis from 2008-14.
The event raised more than $90,000 last year, but its future came into question when the Cardinals did not re-sign Motte this offseason and the Cubs inked him to a one-year deal.
"Initially, we weren't going to do anything here, because we weren't here and we didn't know how everything would go over," Motte said. "We ended up having a bunch of people ask us about it. Our whole thing with our whole foundation is we don't just throw our name on something. If we're going to do it, we want to be there and see the finished product."
Any doubts about if a Cubs player could successfully throw an event in Cardinals territory were quelled by Sunday's turnout and the validity of a cause that has spread through the Majors with the "K cancer" T-shirts that come in the colors of all 30 teams and are associated with a specific player representative from each team.
"It's been great," said Cardinals center fielder and co-presenter of the event Jon Jay, who is now the St. Louis representative for K Cancer. "I was telling someone the other day, what Jason has been able to do with this whole K Cancer movement, it's really special. When we look back in 10 years, I think we'll say, 'Wow, this is big.'"
Players from both teams mingled with each other, and with participants and spectators on the arena floor lined with cornhole boards. Cardinals reliever Randy Choate teamed with Motte, who could hardly maneuver freely without being greeted by a friend or fan wishing him well.
"Jason is just such a good person to bring both teams together, because he's such a good clubhouse guy," Choate said. "Everybody can get along with him and knows he's doing things for the right reasons. He's such a good person that it makes it easy, whether you're his old teammate or his new one, that you want to come out and help support them any way you can."
Fittingly, the bean bags were blue and red, the colors of the teams represented at the event. But at least for a morning, the Cubs and the Cardinals were indeed on the same team.
"The thing is, Major League Baseball is a small fraternity, and when you get in between the lines, you're competing to win," Cubs outfielder Chris Coghlan said. "That's the bottom line. But once you're done, you realize that you're all just human beings, and what we have in common is baseball, and that's cool.
"I think it's a very difficult thing to do when you start something here and then go to a new city, and [the city is] Chicago, of all cities. It's cool that there is still support, and praise God that Jason is as passionate as he is about raising awareness for cancer."