Florida Marlins closer Leo Nunez was placed on the restricted list Thursday and has left the country.

The reason? Two people people familiar with his immigration status told the Associated Press Nunez has been playing under an assumed name, and the issue prompted him to return Thursday to his native Dominican Republic.

Both people said the Marlins have been aware of the issue for several months. They spoke to The Associated Press on condition of anonymity because Dominican and team officials haven't made any public comment on the case.

One of the people said Nunez's real name is Juan Carlos Oviedo and he's 29, a year older than listed in the team media guide. The Marlins placed Nunez on Major League Baseball's restricted list, and he isn't expected to pitch in the final week of the season.

His agent, Andy Mota, declined to comment. The Marlins traveled Thursday to Milwaukee for their final road series of the season.

Before Friday's game, manager Jack McKeon told The Associated Press, "It's the first time I had a, how should I say this, a guy playing with an alias. I don't know what the circumstances are."

This is probably the end of Nunez' Marlins career. He was set to get a hefty pay raise in arbitration this offseason (up to $6 million, some think). The Marlins were unlikely to pay that much for the closer dubbed The Leocoaster for the wild rides his appearances often took.

Nunez has 36 saves and a 4.06 ERA in 68 games this year. His ERA was 2.59 in late May but is 6.00 since then.

The players' association had not immediately determined whether to challenge the Marlins' decision to place him on the restricted list, a person familiar with the union's deliberations said. The person spoke on condition of anonymity because the union had not made any public statements.