Via tweet from SI’s Jon Heyman, Jack McKeon has been named manager of the Florida Marlins and an announcement will come sometime this afternoon.

McKeon is 80; only Connie Mack of the Philadelphia Athletics — who had the advantage of owning the team, so he could keep that job for 50 years — has been the field manager of a team at age 80 or older.

McKeon’s first managerial job was with the Kansas City Royals in 1973, 38 years ago. No current Marlins player was born when McKeon took that job. He has also managed Mack’s old team, the Athletics (in Oakland), the Padres, the Reds and had one other stint managing the Marlins under similar circumstances; he came out of the team’s front office in 2003 when they were floundering and led them to a World Series championship.

It’s not likely the Marlins will repeat that performance this season; McKeon is certainly only a placeholder while the club looks for a permanent replacement this upcoming offseason. Last year there were rumors that the Marlins were after White Sox manager Ozzie Guillen, and nearly completed a “trade” where the Sox would acquire a player in exchange.

Whether or not that ever happens, expect those rumors to resurface after the 2011 season ends.