Guillen discussed some of the issues affecting his struggling squad following Monday's 9-5 loss to the D-backs.
"I think the way we were playing was pretty good, and the last couple of games things got out of hand," Guillen said. "Very lousy baseball."
The fans have noticed too, showering the team with boos over the past two home games, both Marlins losses.
"Can you blame them? I was booing too," Guillen said. "Too bad they can't hear me. It's a shame, because we have a better ballclub than we've shown."
Team president David Samson heard the boos as well.
"Silence concerns me more than boos," Samson said. "People have the right to boo. It's a great ballpark, but we need the team to play better, and they know that. Ozzie knows there are no excuses. It's a bad April, but it's time for May."
Pitcher Mark Buehrle understands why the team is being booed, and hopes to hear those same fans cheering when the Marlins return home on May 11.
"I'd be booing us too with the way we're playing," Buehrle said. "April is gone and we're starting May. Hopefully it's a new month and we can get things changed around. We've just got to keep going out there and battling."
Guillen believes nothing will change until he sees his players making adjustments.
"This game is about adjustments, and we're not making any adjustments," Guillen said. "Day in and day out, we are seeing the same swings, same approach at the plate, the same mistakes."
"People who survive in this game and people who have better days and years are the people who can make an adjustment quickly. If you cannot make adjustments, I will make them for you. That's my job."
Marlins fans should not be surprised if they see some very different lineups in the near future, as Guillen is planning on making some adjustments of his own.
"If the players don't start making adjustments, then I have to do it," Guillen said. "I'm going to make very drastic changes. I don't know what yet. I have a long way to go, a six-hour flight [to San Francisco] to make that decision.
"As a coach, you talk to them, you put them in the best place to compete. You watch video, you give them scouting reports and talk to them. Every question they have, the answer is there. But at the end of the day, the player needs to go out and do it.
"You can come here at eight o'clock in the morning and watch video, take flips, extra hitting, batting practice, extra hitting again and batting practice again. But if you're not making adjustments, then you're not listening or you aren't really working."
Another thing that is beginning to frustrate Guillen is all the discussion about how the dimensions at Marlins Park could be affecting Miami's hitters mentally.
"If they don't want to hit here, they can call their agent and get traded, because we're not going to be here and hit in this ballpark," Guillen said. "We're not going to play defense here and then hit somewhere else. I don't see any problem with any other team. They're kicking our butt pretty good.
"If that's going to be the excuse, that's a no-no to me. We played in Washington, New York, Cincinnati and Philadelphia, and we didn't have that many home runs there either. They're playing for the wrong manager if they think that is going to be the excuse."
While the team's offensive struggles have been well documented, catcher John Buck acknowledges that the Marlins need to work harder to make the proper adjustments in every aspect of the game.
"It's a game of adjustments," Buck said. "Obviously, we're getting beat and things aren't going our way. We have to make adjustments to tighten up our game -- whether it be offensively, defensively or pitching. Hopefully we can do it for the better."
That is exactly what Guillen wants his players to do and he hopes it will happen promptly, because every day they fail to improve is another day they fall in the standings.
"They've got to learn quick," Guillen said. "The talent is there. I still believe we have a great ballclub, but it's not about what I believe, it's about what we show."
David Villavicencio is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.