While the Miami Marlins have made it clear that pitcher Josh Johnson is available in a trade, the team's initial asking price for the All-Star right-hander is so high it's generated skepticism within baseball circles over whether he will be moved by Tuesday's non-waiver trade deadline.

Several baseball sources told ESPN.com the Marlins are asking for each team's top two or three prospects in every trade scenario involving Johnson.

"They're asking for a ton," an American League general manager said.

Another baseball source said the Marlins' demands are so exorbitant that their trade proposals are basically "non-starters" for clubs interested in having a dialogue.

The Rangers, Blue Jays, Orioles, Angels, Braves and Red Sox are among numerous teams interested in dealing for Johnson. Indications are that Miami's talks with clubs have focused on such elite prospects as Jurickson Profar, Mike Olt and Martin Perez in Texas; Dylan Bundy and Manny Machado in Baltimore; and Travis D'Arnaud and Anthony Gose of Toronto.

Several baseball officials have said the Marlins are looking for a haul similar to what Texas acquired from Atlanta in July 2007, when the Rangers landed Elvis Andrus, Matt Harrison, Neftali Feliz and Jarrod Saltalamacchia as part of a seven-player trade that brought Mark Teixeira to Atlanta.

Now that Cole Hamels has re-signed with Philadelphia and the Cubs' Matt Garza is apparently off the market because of health concerns, Zack Greinke, Johnson and Ryan Dempster are the most prominent pitchers available. Unlike Greinke and Dempster, who are free agents this winter and are available as two-month "rentals," Johnson is under contract for $13.75 million in 2013 and won't hit the free-agent market until after next season.