The Miami Marlins want to lock up star outfielder Giancarlo Stanton to a long-term contract this winter, but are not optimistic about getting a deal done, according to CBSSports.com.

The club said before the July 31 non-waiver deadline that it had no interest in trading Stanton.

Stanton and the Marlins agreed to put off negotiations for a contract extension until after the season.

Stanton is reportedly happier with the club now than he was two years ago when it traded off several high-priced veterans, including shortstop Jose Reyes and left-hander Mark Buehrle, among others. However, Stanton wishes to play for a perennial contender, which the Marlins have never proven to be.

Stanton, 24, is eligible for free agency after the 2016 season.

He is batting .289 and leads the National League with 27 home runs, 75 RBIs, 232 total bases and 18 intentional walks.

The Marlins have spent extra time scouting other teams' minor-league systems and players since hiring general manager Dan Jennings a year ago as part of a front-office shakeup. The Boston Red Sox and Los Angeles Dodgers are among the teams that have expressed interest in acquiring Stanton, who is a Southern California native.

The Marlins have stayed near .500 and are 7 1/2 games out in the National League East after losing 100 games last year and 93 in 2012. They have made strides this season, despite being 29th in the majors in payroll at about $50 million.

Stanton is making $6.5 million this year but could command an annual salary of about $25 million on the open market.

But the Marlins are not interested in publicly discussing Stanton's future.

"We're focused on the now," Jennings said. "Win today is what we're thinking about."