Apparently, Cubs pitcher Carlos Zambrano is one of them.
Guillen and Zambrano are close friends, who remain in constant contact with each other.
According to the Venezuelan-based El Nacional, Guillen recently spoke by phone to Zambrano about becoming a Marlin.
Zambrano is signed for $18 million with the Cubs in 2012, and he has a vesting option of $19.25 million for '13, if he finishes in the top four in the 2012 Cy Young voting.
So, if the Marlins are to obtain Zambrano, they would have to trade for him.
The Marlins have made it clear they will explore all pitching options, either in trades or free agency. Zambrano will be given consideration, but according to multiple sources, only if the Cubs pick up a substantial portion of the right-hander's remaining contract.
The Marlins are planning on dramatically increasing payroll, but they are not looking to pay anywhere near the $18 million owed to Zambrano next year.
Last Thursday, the Cubs moved Zambrano from the inactive list to their 40-man roster.
The 30-year-old Zambrano made 24 starts for the Cubs in 2011, going 9-7 with a 4.82 ERA in 145 2/3 innings.
The 6-foot-5, 270-pounder's season ended in controversy after an Aug. 12 loss at Atlanta. He gave up eight runs in 4 1/3 innings, and let his emotions get the best of him. Twice he brushed Chipper Jones back with pitches, and after he was ejected, he exited the clubhouse before the game was over.
In the heat of the moment, Zambrano told Cubs staff and teammates that he was retiring, but changed his story a few days later.
The Cubs placed Zambrano on the disqualified list, and he didn't return for the rest of the season. The Major League Baseball Players Association filed a grievance on Zambrano's behalf, which is still unresolved.