At the Winter Games, a group of curlers exists in a strange paradox: officially Olympians yet uncertain whether they will set foot on the ice.

These are the alternates, the unsung fifths in a sport designed for four.

"My goal is to be always wanted or needed but unnoticed," said Tyler Tardi, the alternate of a Canadian team led by 2014 Olympic champion Brad Jacobs. "If I can be behind the scenes, but the guys know that I'm making their lives easier, that's all I can do, and that's all I can want. It's one of my personal traits, I think, selflessness. It is a big goal of mine to put others ahead of myself. That fits this role pretty well."

The 27-year-old is keen to learn as much as he can from his teammates, who have a wealth of Olympic experience.

"To finally be at the Olympics and to not be on the ice, I don't take that as a negative," he added. "It's more so of a driving force for the future. We're only a few days in, and I already want to be back. This is super cool. I can't wait to work hard and try to be on the main lineup in the future."

One of the main responsibilities of an alternate is to throw rocks the day before a game and map out how each individual stone travels on the ice.

"The rocks run a little bit differently sometimes," said U.S. alternate Rich Ruohonen. "That's the main thing. Also, just doing anything I can to help the team. Carry the brooms, go make sure everybody's up in the morning, make sure people are where they need to be when they need to be there, change the broom heads before the game.

Ruohonen, who last week became the United States' oldest Winter Olympian at 54, said he is also serving as a mentor to his teammates, who are all in their 20s. He spends time re-watching games and scouting the coming opponents. 

"I'm trying to help these guys. We have the youngest team here. They still have a lot to learn," he added.

While alternates rarely get on the ice, it is always a possibility, and it is vital to be ready.

"I fully appreciate that the chances are that I'm not going to play in a game," said Great Britain alternate Kyle Waddell. "I make sure that I'm in the mindset that I can play, because at the end of the day, if I do need to come on, then I'm not making Team GB any weaker.