Brown sat out the offseason program and is missing camp because of a contract dispute. He has two years left on his contract and is due a $9.4 million base salary this year.
"He ought to be here," McNair said, echoing Smith last week. "He needs the work just like everybody, so we look forward to his coming back."
Brown has given no indication when he'll report. Game checks begin the first week of the season. Players are paid over 17 weeks in regular season.
"I'm sure he'll be here," McNair said. "It's just a matter of when."
McNair watched practice in a golf cart next to his wife, Janice. He spent close to $4 million to move training camp to The Greenbrier Sports and Performance Center.
The Texans believe the cooler weather will help them win more games.
"It's a beautiful place," McNair said.
"The facilities are great. We had a productive practice for 2 1/2 hours. I don't think we could quite do that in 100-degree weather (in Houston), so it's been very productive."
McNair predicts the Texans' offense will improve, and the defense will be even better than last season, when it allowed the fewest yards in the NFL.
"I guess the most exciting thing is to see the improvement in our offense I think we'll see," he said. "I think it's going to be a little more productive.
"I think our run game is so important to us and that we've got multiple running backs that can do well. I think that our passing game's going to be better. We've got some good, young receivers."
Like everyone else, McNair is eager to see what quarterback Tom Savage can do once the season begins.
"I think they're going to be able to put more points on the board," he said. "It's a chance for Tom to get out there and show what he can do. He's talented. It's a good group.
"Our defense was outstanding last year. I think we're going to have a big improvement in our offense this year, and the defense is going to step it up a little, also. We ought to be well-balanced. I'm really looking forward to it."
Watt has gotten two days off. He said last week the coaches were going to take it easy on him as he eased his way back to full contact. He should be back on the practice field Wednesday.
"We're just trying to manage him," coach Bill O'Brien said. "He's ready to go. He's in great condition, and I think it's important to get him ready for Sept. 10."
That would be the regular-season opener against Jacksonville at NRG Stadium.
As for Johnson, O'Brien said, "Day off. Nothing to read into (it)."
Every day after practice, O'Brien patiently answers questions about quarterbacks Tom Savage and Deshaun Watson.
"Tom's had a really good training camp," O'Brien said Tuesday. "He had a good day today. Deshaun is really way ahead of any rookie quarterback I've been around."
O'Brien is excited about the offense at this early stage of camp.
"I believe in it," he said. "I believe in mixing it up. Speeding it up, slowing it down. Huddling, no huddling. I think our guys really understand our offense now.
"It's been fun. It's not just defensive-dominated, and I think that's important for the team. Now, of course, we've got to do it in a game, but I'm happy with where we are right now."