McNamee's announcement came a day after Australian hardcourt championships director Colin Stubs said the former world number one, who retired at the start of 2003, would play doubles as a wildcard entrant in that event next month in Adelaide.
However Stubs said Rafter, who turns 31 on Sunday, was not planning a comeback to the professional circuit and McNamee refused to speculate on the topic on Wednesday.
"He'll be a really good addition to the tournament and for the fans in particular. The fans will get a kick out of it," McNamee said.
"It's been on the cards for a while, especially when Pat was ordering the tournament balls a few weeks ago. That's always a positive sign.
"It'll be interesting to see how he goes. He and (doubles partner) Josh (Eagle) will have had a game in Adelaide (January 5-11) and that will have them in good stead for Melbourne (January 19-February 1)."
Rafter announced his retirement in January 2003, more than a year after he played his last competitive match when Australia lost the Davis Cup final to France 3-2 in Melbourne in December 2001.
"It's great that he has confirmed this early that he is playing. It's a real bonus for us," Australian Open spokesman John Lindsay said on Wednesday.
One of the few genuine serve-and-volleyers to succeed in the modern game, Rafter won the 1997 and 1998 U.S. Open titles and briefly reached the top of the world rankings in July 1999.