When matches go to five sets at Wimbledon in the coming fortnight he will be on hand to relieve cramp in the calves and when rain intervenes he will be there to ensure that it does not afflict minds. A massage there, a message here and players ranked from one to 500 can be up and running again. As a sports medicine trainer employed by the ATP for these past 25 years he might not quite recognise them all but he has no favourites.
"The main difference between now and when I started in this is the reaction of coaches and parents," he said. "They can be so involved with a young tennis player and it can be hard for the kids to know how to cope. I'm here to provide help to the world No 798 just as much as anybody in the top 10. They don't all seek me out but they all know I'm here.
"There is a big number of kids who come into the game and the game is all they have known. This can take a lot to contend with because they have not grown up like others of their age. That's where I and my colleages can increasingly come in."
Norris was the man who worked furiously on a cramped, dehydrated, tired but game 39-year-old Jimmy Connors at the US Open in 1991 when Connors reached the semi-final. Throughout the tempestuous career of John McEnroe he was around to offer advice on the temper tantrums. "John was such a perfectionist and he was very hard on himself, but playing that way also worked for him. I'd advise him but I'd also advise others on how to deal with it. I really am not biased in anybody's favour. My job is to help even if there are two players coming up against each other in the same match."
He is an expert on the workings of the body but he was dispensing wisdom on the importance of psychology long, long before it was fashionable for sportsmen to have couches as well as coaches. Norris first came into contact with tennis players at Madison Square Garden where his tasks embraced rather more than dealing with the occasional professional tournament in pre-open days. He was sports medicine trainer to the New York Nicks basketball team, was expected to help boxers who fought there and if The Beatles or Frank Sinatra were in trouble while performing at the Garden it was Norris who would turn up to provide succour.
He became specifically involved in tennis through Lamar Hunt's organisation, World Championship Tennis, and has remained with the sport since. That is a track record which has seen him through four or five generations of tennis players from Rosewall and Laver to Sampras and Rios via Smith and Nastase, McEnroe and Borg.
"So often the hard work isn't just in curing an injury whether it be a nerve or a pull but in persuading the player it's cured. They can still feel it or think they do and won't quite go for it. I've got stock phrases for them, to help them through from 'touch the shoelace on your right shoe' to 'remember the last time you played so and so and it all came right'."
Norris's first job in landing in London from Florida on Friday was to contact the injured Greg Rusedski and Mikael Tillstrom to see if he could help to speed their recovery from injury - definitely physical in both cases. He might have a few words of comfort for Marcelo Rios, the tournament's No 2 seed who was much criticised for his exit last week in the grass- court competition at Nottingham where it was suggested he seemed not to give a jot.
"I've got to know Marcelo the last couple of years. He's a very shy guy. There's a complex background but he's come into his own and is certainly accepted more by the players." Norris is aso excited by the advances of Scott Draper, the Australian outsider who won at Queen's and he sees the good in them all. He refused to tip a winner at Wimbledon. No favourites then but he is extravagant in his praise for Jim Courier, a player of only 27, who was once No 1 in the world and is now not even in the top 20.
"At one time he was obviously suffering from some kind of burn out and there might have been a lot of emotional scars. We had a lot of talks. Jim slipped down the rankings but he could have slipped out of tennis altogether. He didn't, he took stock."
Norris at 55 resembles (and has regularly been mistaken for) the late pop singer John Denver with his mop of blond hair, round spectacles and face to match. But he is more like fiction's favourite old-time school teacher, Mr Chips, who on describing the number of his children said he had "thousands of 'em, thousands of 'em - and all boys".