Castro and Lackey exchanged words near first base, with Hinske and Molina both stepping in. At the end of the Cubs fifth, Hinske and Lackey had an exchange again as the coach was trotting back to the visitor's dugout.
Lackey wouldn't comment on what happened. Castro was still trying to figure it out.
"When I missed a pitch, I said something to myself in Spanish," Castro said. "[Lackey] said something, but I didn't really hear what he said. I come back, and Molina told me, 'Don't worry about it, stay away. It's nothing.'
"Everybody has different emotions, everybody doesn't have the same emotion," Castro said. "If you miss a pitch, if you miss location, you get mad, too. If you miss a pitch, everybody gets mad. I didn't say anything to him. I don't understand. I didn't [mean to] offend him."
Castro could've been upset at Lackey, who had hit the shortstop on the shoulder with a pitch in the first inning. But he wasn't.
"I said something in Spanish about me, not to [Lackey]," Castro said. "I didn't really hear what he said."
Was Castro surprised that Lackey confronted him?
"Yeah, I was surprised -- that never happened to me," Castro said. "Yadi told me, 'Don't worry, it's nothing.'"
Cubs manager Rick Renteria said he wasn't sure what was going on. Hinske was in the middle of it.
"[Castro] apparently said something that John didn't like, and John said something to me," Hinske said. "I asked him, 'What are you talking about?' because I didn't know what he was talking about. [Castro] is competing. Yadi came over and said, 'Just chill out,' and I said, 'I don't know what [Lackey] is talking about.'"
Lackey continued his conversation with Hinske after the fifth.
"The next inning, [Lackey] came over and explained what he had a problem with, and I told him, 'OK, let's chill out and relax,'" Hinske said.
Hinske didn't want to reveal any more details. This is his first year as a Major League coach after 12 years as a player. So, he's a peacemaker now, too?
"Yeah, I'm a coach now," Hinske said.
When asked if he'd explain what happened, Lackey's only comment was: "No."
"They were just talking," said Cardinals manager Mike Matheny.
Did they get it sorted out?
"They must have, yeah," Matheny said. "I think Lackey initiated that conversation and Yadi helped summarize."
The Cubs lost Sunday's game, 9-6, and split the four-game series against the Cardinals, but gained a lot of experience.
"It was good for them to play a game like that," Hinske said. "You never want to lose that game, but that was playoff atmosphere right there. Getting that experience under their belt, knowing what it was like to feel that, and all that intensity [will help].
"When you're up with two outs in the top of the ninth and guys on second and third and you're in front of 50,000 people, you can't duplicate that," Hinske said. "It's really good for all these young guys to see. It was an emotional game. It was fun. The only bad part is losing. Hopefully, we keep on continuing to work and get on the right side of those games."
This is just another chapter in the Cubs and Cardinals rivalry.
"It's emotional," Castro said. "That's a team fighting to make the playoffs, and we don't make the playoffs this year. They're mad when we win, when we beat those guys. We're baseball players, too, and we have a good team, and we try to play hard every day."
The teams meet again Sept. 22-24 at Wrigley Field.