"I was just catching up with an old friend and encouraging him to be the best he can be, both on and off the field. And that's part of my job here," Sweeney said.
He encouraged Butler to join teammates like Alex Gordon and James Shields in taking a more visible leadership role with the Royals.
"Challenged him to be a fountain, breathe life into these guys. I was sharing with Billy: In the big leagues, you look at guys and they're either a fountain or a drain, they're either sucking the life out or pouring life in," Sweeney said. "I was just challenging Billy: 'You're one of the best hitters on the planet, so be a fountain from Day 1.'"
Butler is one of only three players remaining from Sweeney's Royals days, which ended in 2007. The others are Gordon and Luke Hochevar.
"It's good to see him," said manager Ned Yost, "because he is very energetic, he is very positive and our guys in our locker room, the vast majority, are real positive and energetic, too. So he fits in real nice."
Sweeney will spend a week in camp, then return twice during March before the Royals head into the season.
"He'll give little tidbits of information to players that help them," Yost said. "Every player every day should be looking for something minute, something very small that's going to improve his game. Because nobody at this level is going to find something great that's going to turn their game around -- it just doesn't happen. You start adding up the minute areas, try a little something here, a little something there, and all of a sudden, they start to become better players. That's what he and Jason Kendall and George Brett bring to the table."
Kendall, a former catcher, is in camp now in his continuing role as a part-time instructor. Hall of Famer Brett usually arrives when the infielders and outfielders report.
Sweeney, obviously, was delighted to be back.
"It feels like the first day of school," Sweeney said. "I was walking around, where am I supposed to go, who are the new teachers, who are the new students? And I'm one of them. But it's all about these players, this team has nothing to do with an old, broken-down guy like me. It has everything to do with them."
Sweeney once presided over the clubhouse as the team captain.
"Now I'm just a deck hand," he said with a smile.