No. 5 Hanley Ramirez
The 26-year old Hanley Ramirez has already established himself as one of the best offensive players in baseball. What makes him especially valuable and the fifth most indispensable player is that he plays a position that has long been valued as a defense-first position.
The Florida Marlins shortstop is a true five-tool player with the stats to match. With his improvement in the field over the past couple years, Ramirez has no weakness.
The 6' 3", 230 pound player has accumulated a .316 lifetime average, including an NL leading .342 in 2009. In his first four full seasons, Ramirez has averaged 118 runs, 26 home runs and 41 stolen bases.
Losing Ramirez would rob the club of its best player in four categories— batting, power hitting, base running, and fielding. The notoriously frugal Marlins recognized his tremendous value to the team by signing him to a six-year, $70 million contract extension in 2008.
Note: This was written prior to Ramirez's benching for lack of hustle. I would anticipate that the matter will be quickly worked out and Ramirez will have additional motivation to excel.