DENVER -- Louis van Gaal says the 2 p.m. kickoff time for Manchester United's preseason friendly versus Roma on Saturday is "unbelievable."

Temperatures are predicted to reach 90 degrees, and Van Gaal revealed he will request that water breaks are taken during the match, just as they were when his Netherlands side overcame Mexico in the World Cup round of 16 last month.

Van Gaal said, "I shall convince the referee like I did in Fortaleza," and added that just two players -- Tom Cleverley and Tyler Blackett -- will play all 90 minutes. One man who will not feature is Rafael after the defender left Friday evening's training session at Sports Authority Field with what appeared to be a groin injury.

Van Gaal expects to make nine substitutions at half-time on Saturday. Kevork Djansezian/Getty Images

The clash with the Giallorossi is United's second of the preseason -- following Wednesday's 7-0 win over the L.A. Galaxy -- and the first in the International Champions Cup tournament. Having spent just more than a week with his new team, the new United boss spoke about his initial impressions of the players.

"They are willing to pick up all information that we show and say, and that is very important," Van Gaal said on Friday evening. "They want to perform our philosophy and, OK, we have to wait and see how it develops."

Van Gaal admitted that Friday's first practice, which featured a simulated game in preparation for Saturday's match, was "not a good session" but said he was pleased with the evening's work, which focused more on positional play.

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The Dutchman also revealed a little of his coaching philosophy, which, he says, challenges the minds of his players and is very demanding.

"The most important difference is that I am training the players, not in the legs, but in the brain, in brain power. That's the big difference. That's not so easy for most of the players. And my direct character -- I say the things how they are, so that can be good and that be worse, also."

United face a Roma side that beat Liverpool 1-0 in Boston on Wednesday but which will not feature injured Netherlands midfielder Kevin Strootman, who has been linked with a move to Old Trafford.

When asked about the man he coached for the Dutch national team, Van Gaal indicated that he will be watching his eventual comeback closely.

"Strootman I can judge, but he is injured for more than six months. We have to wait and see how he is coming back. It is not so easy to come back after an injury, so we wait and see."