Coming off a four-game split with the Nationals, the Marlins opened a three-game set against the Cubs at Wrigley Field on Tuesday.
"It's up to the players," Marlins manager Ozzie Guillen said. "If we're playing good this week, they'll be fine. If we're not, that's everywhere. That's everywhere with teams in our situation. If you want to stay here, just win some games."
The Marlins have a standing policy of listening to possible offers for any of their players. That said, the club has no intention of trading slugger Giancarlo Stanton.
If the Marlins fall further back by the end of the month, right-hander Anibal Sanchez could be a possible trade candidate. Sanchez is a free agent after the season, and Miami hasn't sought to sign him long term.
Guillen noted that the players need to do their part right now and show they can make a playoff push.
"I want everybody here," Guillen said. "The front-office people want everybody here. A few people want to finish the season with the players we had from the start. They want to win this thing.
"It's up to the players. If they play good, nobody is going to leave. If that play bad, that's part of the business."