"That means, 'When David wants it, David takes it,'" Speraw said. "Because in the middle of a play, you can't call him off."
The reason? Smith is nearly deaf and primarily uses lip reading to understand his teammates. In volleyball, such face-to-face communication is not always possible.
Hence the David Smith rule.
It was easy for Speraw to institute the rule because when Smith gets the ball, he knows just what to do with it.
"He's mitigated any issues he has by being a great all-around volleyball player," Speraw said.
Smith, 27, is a first-time Olympian with the U.S. men's volleyball team, which opens play at the London Games on Sunday with a match against Serbia. Speraw is an assistant coach with the team and one of Smith's biggest supporters.
Smith was born with his disability. He says that his doctors believe that that his hearing loss is in the 80-90 per cent range and he has worn hearing aids in both ears since he was 3.
"Every once in a while it affects me," he said. "But this is the only way I've ever known how to play."
Really, the main problem is that sometimes when he sweats a lot, the hearing aids go out.
"But I just got these before the Olympics and I don't seem to have any problems," he said, raising both hands to his ears.
Smith was something of a surprise addition to the U.S. team in London. The 6-foot-7 middle blocker was not on the roster when the men qualified for the London Games at the NORCECA Olympic qualification tournament in May.
"It has been a crazy summer, that's for sure," he said. "There were some opportunities that came up for me to show what I could do, and I think I did a good job with that. I wasn't counting on being here, but I knew I was capable of being here."
Four years ago, the United States won the gold medal in Beijing, going undefeated and upsetting favourite Brazil in four sets in a thrilling final.
The men are currently ranked No. 5 by volleyball's international governing body and are coming off a silver medal finish in the FIVB World League. Since volleyball became an Olympic sport in 1964, the U.S. men have won three gold medals, at the Los Angeles Games in 1984, the Seoul Games in 1988 and in Beijing. The men won the bronze in 1992.
The team is in a difficult pool in London, joining top-ranked Brazil, perennial powerhouse Russia, Serbia, Germany and Tunisia. The other pool includes Italy, Poland, Argentina, Bulgaria, Australia and host Britain.
Smith picked up volleyball in high school. He originally committed to another college, but Speraw persuaded him to come to UC Irvine and he was part of the team that won the 2007 national championship.
He graduated from Irvine with a degree in civil engineering. He has his license, even though engineering is on the back burner for now. Like many players at his level, Smith plays professionally overseas for a living. Last season he played in France.
"I think the thing that separates him from some of the other players is his physicality," Speraw said. "He really does jump very well, so he can physically match up with players who are much bigger than him. That physicality is what we saw that we thought would separate him."
But Smith never dreamed he'd be an Olympian.
"I still can't believe it," he laughed.