The Marlins, in cooperation with MLB.com, are offering fans the opportunity to purchase the remaining unsold tickets -- at face value -- from that game. The tickets can be bought at www.marlins.com.
A crowd of 25,086 was on hand to watch Halladay retire all 27 Marlins he faced in the Phillies' 1-0 victory at Sun Life Stadium.
"There have only been 20 perfect games in history," Marlins president David Samson said. "To the extent that there is any demand for tickets for that game, and there is an availability of tickets, this just made sense."
The White Sox and Athletics did something similar for the perfect games pitched by Mark Buehrle and Dallas Braden, respectively.
Samson noted that in the first four hours tickets went on sale, 3,000 were sold. A majority of them have come from the Philadelphia area.
"As long as tickets are available, we'll keep selling," Samson said. "We'll keep going, the same way we would for a World Series or any other game. What we do is open up different sections."
Because tickets for the historic night are going to continue to be sold, the attendance figure for the game will be revised.
"It would have to be," Samson said. "Any ticket revenue is part of revenue sharing and part of the local revenue. So it gets reported."
The exact number of tickets available will be roughly 40,000 more. Samson added that tickets for the game will remain available throughout the entire regular season.
"We'll see what the demand is," Samson said. "Remember, no matter how many tickets were ever bought, 20 years from now, 300,000 people will say they were there anyway."
Halladay and Florida's Josh Johnson engaged in a classic pitching matchup. In defeat, Johnson allowed one unearned run in seven innings. Halladay, meanwhile, struck out 11.
After the gem was thrown, the Marlins presented Halladay with the pitching rubber from the game. In addition, home plate was removed. The Marlins plan on making it part of the history display in their new ballpark, which will open in 2012.
"It's baseball history," Samson said. "We're just selling tickets. To me, it's natural. We're just selling tickets. We're not misleading anybody. No one is buying a ticket thinking they are going to the game. No one is going to the game saying, 'I wonder who wins?' It's not as though that there is any consumer fraud going on. These are people who are well aware of the result."
Joe Frisaro is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.