From Gaslamp Ball Wiki - A Wiki for San Diego Padres Fans

Often placed after a player's name in ironic fashion immediately after the player fails to do something productive, such as get a hit with runners in scoring position and two outs.

For example, with 2 outs and a runner at second base, David Eckstein might ground out weakly to shortstop. A GLB'er would then say, "David Eckstein: Superstar."