Minnesota Twins outfielder Denard Span and Philadelphia Phillies free-agent-to-be Shane Victorino are potential trade targets for the Miami Marlins, speculates FOX Sports’ Ken Rosenthal.

Rosenthal believes it will be difficult for the Marlins to upgrade their offense this summer because their minor league system is thin. Rosenthal believes Miami’s most obvious need is in center field with regular Emilio Bonifacio on the disabled list.

Unfortunately for the Marlins, Rosenthal says center field options on this summer’s trade market are limited.

The Twins are reportedly willing to listen to offers on Span, who Rosenthal believes makes perfect sense for the Marlins. A holdup could be that, due to Span’s reasonable contract which includes a team option through the 2015 season, the Twins will ask for a significant return for their center fielder.

Rosenthal believes Victorino could hit the Marlins radar if the Phillies decide to sell this summer. The Flyin’ Hawaiian is in the final year of his deal and is making $9.5 million this season.