"I think this was a minor procedure and he'll be ready once training camp starts, maybe the middle," McNair told reporters from the team's charity golf tournament, according to KILT-AM in Houston.
Reed underwent arthroscopic surgery late last month to repair a labral tear in his hip.
A nine-time Pro Bowler, Reed left the Super Bowl champion Baltimore Ravens after 11 seasons to sign a three-year, $15 million deal with the Texans in March.
Texans coach Gary Kubiak said Reed needing surgery came as a surprise.
"We didn't expect it but it started bothering him. He's had this issue on the other side before. So once it started happening, that's when we got aggressive in what we needed to do to get him ready to play the season," he told reporters.
Defensive coordinator Wade Phillips said the timing of Reed's surgery makes it a concern since it didn't come right after the season but he's confident Reed will be able to quickly make up for whatever time he misses with the team.
"He's an experienced guy. You have no problem with him studying or knowing what you're doing," he told reporters. "He's going to spend all the time it takes off the field to get ready. I think Ed will be ready when it's time."