"Do you want to play a soccer game here in January?" Manning said Thursday, after being asked about Garber's remarks to The Washington Post. "There's idealism, and then there's realism. This is a very large country with different time zones and different weather climates. For me, it's just not feasible to play the calendar they play in England or Spain."
Garber has said a change could come eventually for MLS.
"In order [to become one of the top soccer leagues in the world], we have to measure up against all the other leagues and more than likely have a similar calendar," he told the Washington Post.
But there are other countries that aren't playing that schedule (Norway, Sweden, Finland, Australia, Brazil, China and Japan, to name some of them).
Until every team has its own stadium and completely controls its own scheduling, Manning said it would be impossible to change. And even then, winter weather could hurt attendance and performance.
"Russia just changed their schedule within the last year, and I know there were some games in Russia this year that were just abysmal," he said.
RSL has had decent weather and has been able to sell out its home-openers the last two Marches. But colder weather still keeps fans away in the early goings (RSL sold out nearly every home match from July on last year).
"One of our big fears is we get one of these 25-degree days with a foot of snow and we have to play a soccer game," Manning said.
As it stands, RSL starts preseason training in January and begins playing preseason games next month in Arizona. A team could play into early December if it were to make the MLS Cup.
"The league is continuing to grow and its doing extremely well," Manning said. "Really, if you look at our schedule, with the exception of July ... it almost matches up with the FIFA-preferred calendar."