Cats are in safe hands with Ben.
According to popular thinking you do not have to be mad to be a goalkeeper, but it certainly helps.
After all, anyone who stands around waiting to dive at the feet of an on-rushing striker, fling himself in the way of a point blank shot or try and claim a cross against a burly centre-half, must have some sort of mental deficiency.
And then there are the hours of training, the repetition of shot after shot, save after save, with just a couple of like-minded souls for company while your teammates run around traffic cones and play the odd-spot of one-touch six-a-side.
It is a lonely existence and a position which, more than any other on a football pitch, owes as much to mental strength and concentration as it does to raw talent.
"They have to stand there in training and have balls whacked at them from all directions for two hours," explained McCarthy, as he attempted to explain his conviction that Ben Alnwick is ready for Championship football.
"It's a lonely existence which makes you a tougher character. You certainly get the treatment in training and in matches. You have to be a strong personality, as well as a good goalkeeper."
Perhaps that is where the explanation for a goalkeeper's stereotypical eccentricity lies.
Just as it is said there is a thin line between a genius and a madman, such is the shared intensity of thought, perhaps the dividing line is equally narrow between those with a screw loose and those who choose to operate as a football team's last line of defence.
Yet, like all stereotypes, the image of the clown prince goalie is simplistic and misleading.
For every extrovert like former Liverpool goalkeeper Bruce Grobbelaar, or ex-Sunderland and Newcastle stopper Lionel Perez, there is a restrained character like United and Ireland number one, Shay Given, or the greatest of them all, England's 1966 World Cup winner, Gordon Banks.
And it is from the latter group that Sunderland's trio of net custodians appear to draw their inspiration.
While Mart Poom and Thomas Myhre are highly-rated, they are hardly renowned for extravagant acts of showmanship or outrageous comments.
And it is from this professional mould which Alnwick, according to McCarthy, is trying to forge his own career path.
With Poom still ruled out with a knee injury and Myhre a doubt with a shoulder injury for this afternoon's meeting with Watford, Alnwick is in line for his first start for the Wearsiders.
But, while the 18-year-old from Prudhoe is untried at senior level, McCarthy, who was among the first coaches to spot Given's potential when he was coach of the Republic of Ireland, is convinced the England youth international is destined to shine at the top level.
He explained: "I'm hopeful that Thomas Myhre will be fit, but if he isn't I've got no qualms about playing Ben Alnwick. He wouldn't be on the bench for games if I was scared to play him.
"He is involved in the England youth set-up and he is a terrific young goalkeeper.
"The way he performs in training and the way he has played for the reserves, he conducts himself very well. He is a confident young man and you can tell he is going to be a top goalkeeper. When I was manager of Ireland I gave Shay Given his debut when he was 18 or 19 and there were a few eyebrows raised then. But you could tell he was a top quality goalkeeper and look where he is now.
"It's the same with Ben. He has a great presence, he is a dominating figure in his goal. He saves shots well, but he also takes the ball well from crosses and commands his area.
"In some respects you could say he is old beyond his years, but he is just a good goalkeeper, they are a special breed."
A special breed indeed. While McCarthy may have put forward a convincing argument to illustrate the sensibility of his pool of goalkeepers, even he suggests the very nature of the position makes them abnormal.
He added: "The other day, Michael Ingham was in the nets and he was getting bashed repeatedly because shots were coming at him from all directions.
"I tried to show him a bit of sympathy, but Taff (assistant manager Ian Evans) said ` sod him, he didn't have to be a keeper, he should have been a centre-half, the silly boy.'
"There is a saying that all goalkeepers are mad and I've met a few in my time who are off the wall. If you choose to be a goalkeeper there must be something slightly odd about you. I mean, who wants to stand there while shots are flying towards you at 50 or 60mph?
"But, if you look at players like Mart Poom and Thomas Myhre, they are good, calm characters. If you look at Shay Given, he is the same.
"I think Ben will be like them, but only time will tell how good he can become."