"I fixed it," Marmol said Tuesday. "It's not a good thing. I know what I have to do."
Hitters and pitchers usually keep to themselves, but Byrd, the new guy in the clubhouse, is doing what he can to help.
"He talked to me," Marmol said. "He's my teammate. I don't want somebody else to see my pitches."
Tipping pitches is definitely not a good thing, and veteran hitters can usually spot it before pitchers do.
"When I came to the big leagues, Bobby Abreu and Ricky Ledee taught me about pitchers tipping pitches," Byrd said. "That's one thing I've gotten better at over the years. I can see when guys are tipping.
"If they are -- and they're my teammates -- I want to make sure if I see it, then veterans on the other team can see it," Byrd said. "Hitters have the edge, they always have the edge. If you know what's coming, it makes it a little bit easier. It's not easy, but a little bit easier."
Byrd picked up something in Marmol's delivery. He also saw right-hander Thomas Diamond telegraphing his pitches, as well.
"Anything I see, I'll tell them because I'm trying to help our guys," Byrd said.
Diamond appreciated the feedback, and he'll do the same for hitters.
"If we see something with them and we're trying to exploit something that they might be doing as a pitcher, we might tell them, 'I was working you this way because I saw this and you showed me this,'" Diamond said. "For the most part, they're giving us a lot more feedback."
Diamond, a non-roster invitee who was claimed off waivers from Texas last September, has talked to Byrd, Ryan Theriot and Jeff Baker, so far.
"I've gotten some really good feedback," Diamond said. "I appreciate it. It's been really helpful."
It isn't that the Cubs' pitching coaches aren't making comments.
"The pitching coaches are looking more at how our mechanics are, not [whether a] leg kick or hand break or arm pattern is giving away anything when we're throwing," Diamond said. "The hitters are looking for that stuff. It's good to get that feedback, especially from teammates."
Byrd also doesn't hesitate to tell a pitcher when he's doing well, either. He faced Jeff Stevens on Monday, and the young right-hander threw a curveball that prompted an appreciative yell from the outfielder.
"You have young guys and they have a big league hitter in there, and I think they'd want to know if something is looking good or if there's something they need to work on," Byrd said. "Pitching coaches do their thing, but if hitters give them feedback and give them that confidence that everything they're doing is right, they don't have to second guess themselves."
Stevens said he didn't know exactly what Byrd said but appreciated the reaction. He has been working on his slider with pitching coach Larry Rothschild and was told to throw his curve now and then to keep it sharp. He only threw two curves, and one of them fooled Byrd.
But the outfielder isn't looking at changing careers down the road.
"No, I know nothing about pitching," Byrd said. "But I can tell you when guys have nasty stuff. I don't know anything about the mechanics of pitching."
Greg Maddux would talk to hitters and hitting coaches. Byrd is just trying to help.
"If you're facing Randy Wells," Byrd said, "you know he doesn't tip his pitches and he throws the ball moving everywhere. I'd have one approach -- you try to go the other way with him. If he knows that and knows certain hitters, he knows, 'I have to stay in -- in, in, in, in -- then something away to change their eye level' and stuff like that.
"You can go over that with your pitching coach all day long," Byrd said, "but the hitter gives just a little bit different feedback."
And it's all good.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.