Alderson, 67, was conducting a question-and-answer session with reporters when he fainted, falling to the ground. Several seconds later, he came to and a reporter helped him to his feet. Alderson even cracked a joke after he regained consciousness, walking out of the room without assistance.
A Mets official said Alderson had not eaten breakfast, and felt "a little lightheaded" due to the bright lights and heat in the Mets' news conference room.
"He's fine," the official said approximately 10 minutes after Alderson collapsed.
Anthony DiComo is a reporter for MLB.com. Follow him on Twitter @AnthonyDiComo and Facebook, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.