Struggling in the standings, the Marlins have already been mentioned as a team willing to make moves before the July 31 non-waiver Trade Deadline.
For now, the team is not considering dealing two of its top relievers.
According to a league source, the Marlins have told clubs that closer Steve Cishek and hard-throwing lefty Mike Dunn are not available. Both are under club control this season, and reach arbitration next year.
The Marlins, however, are open to dealing starter Ricky Nolasco, who will be a free agent next season. A source says Miami likely would get a mid-level prospect for Nolasco.
Reliever Ryan Webb, in arbitration for the first time, also could be dealt for the right offer.