Mariappa has three daughters and a young son. "My youngest daughter loves football," he says. "She got the away kit recently and won't take it off."
They must have wondered what on earth daddy had been doing when he came back to their Watford home around this time last year with a nasty gash above his right eyebrow and a pronounced limp.
"Me and Daryl [Janmaat] went up for the same ball and managed to split each other’s head open," said Mariappa. "When I landed I managed to get a tear in my medial ligament. It wasn’t great."
You wouldn't mind but they were on the same team. Chaos ensued and it was like a scene from Holby City in the dressing room at the training ground.
"There were people rushing around," he said. "We both got rushed to hospital with nasty cuts. I got stitched up in the dressing room because it was flapping open. Other people were a bit more squeamish than me. I remember the doc's hand shaking as she was stitching me up, so I knew then it was a bad one."
Mariappa now has an impressive war wound on his forehead and a nice line in gallows humour.
"I can’t move my right eyebrow much now," he jokes, "but I wasn't going to have a modelling career so I wasn’t that worried about the cut. I was more concerned about my knee."
The knee problem kept him out until January, when he played in the ill-fated FA Cup tie at Millwall, but it took him until April until he got a sniff of league action, against West Brom. He helped the team preserve a clean sheet in that full-throttle game under the lights and got another in the next home game against Swansea. That, however, didn't make him immune from being harshly dropped for the trip to the KC Stadium for the game against Marco Silva's Hull. And we all know what happened on that wretched afternoon.
"I remember that one," Mariappa said. "We'd just come off the Swansea win and getting a clean sheet. I was happy and performed well and the manager decided to take me out the team. That’s his decision but, as a player, it’s not nice as you just want to play, especially when you deserve to play. I respected his decision and just cracked on with training. You can’t sulk as it doesn’t get you closer to playing. I just got my head down and tried to prove that I should be in the team."
It's a maxim that continues to serve Mariappa well, one that chimes with Marco Silva. The Head Coach's touchstones are based around hard work.
"The gaffer gave me the opportunity this season and, thankfully, I’ve stayed in the team and put a run together. You can't predict things or get ahead of yourself. All you can do is train hard and show the manager that you deserve to be in the team."
And boy has he done that, particularly away at Swansea. He had Wilfried Bony in his pocket, regularly outjumping the Ivorian and then producing the goal-saving tackle of all goal-saving tackles to deny Tammy Abraham. It was the centre-piece of a towering performance.
"It was a good block and I was glad to contribute something to that game," said Mariappa with typical understatement.
He was just as good against West Ham, showing off his prodigious leap to outgun the giant Andy Carroll in the air and then when he did make a mistake, against Manchester United, he recovered to block Lukaku's goal-bound effort. Richarlison, Kiko Femenía and Abdoulaye Doucourè have been the talk of the town but Mariappa has been impressively going about his business with minimal fuss. He can rarely have played better in his career than he is right now, especially when you factor in the calibre of opposition.
"I think I’ve been in good form this season," he said. "The manager demands high standards in training every day and the squad improves as a result. When you are training against our forward line then you are very prepared for who you come up against. I just love defending. I love tacking, blocking and heading the ball, I’m a bit old-school. I like spoiling attacks and not letting a striker getting their way. I take real pride in that and really enjoy it."