Dec 16 (Reuters) - North America"s major leagues were struggling to contain an explosion of COVID-19 outbreaks on Thursday as fans were bracing for a holiday season of disruption. For three days the National Football League, National Hockey League and National Basketball Association have faced a surge in positive tests, with more expected on Thursday, forcing players into league mandated COVID-19 protocols and the postponement of games. The holiday season across the United States and Canada is usually filled with sport action with everything from college football Bowl games to the NBA"s Christmas Day showcase. There is no indication yet that any holiday action will be postponed but with the coronavirus spreading through locker rooms, fans may not see all their favourite players. In Canada, those who get tickets as Christmas presents to the NHL Toronto Maple Leafs and Ottawa Senators or the NBA Toronto Raptors may not be able to use them. The Canadian and Ontario provincial governments announced a 50% reduction in arena capacity on Wednesday as part of new restrictions to combat the fast-spreading Omicron variant. Despite seeing almost 100 players enter COVID protocol this week, the NFL has not postponed any games and has no plans to limit stadium capacity. "No discussion of that," the NFL told Reuters in an email. "With few exceptions, players don’t interact with fans on Game day anyway." Already dealing with a backlog of 10 postponed games, the NHL on Thursday was looking at the possibility of more scheduling headaches. With COVID-19 running rampant through their locker room the Calgary Flames said on Thursday that two more players had entered protocol bringing the total to 18. With almost the entire team in quarantine, the NHL said it was delaying Calgary"s return to the ice until at least through Dec. 18. The International Ice Hockey Federation, which organises the world junior hockey championship that will be held Dec. 26-Jan. 5 in Alberta, did not immediately respond when asked by Reuters in an email if there was talk about limiting attendance. The premier of the western Canadian province, however, said this week there were no plans to change capacity levels in the two arenas that will host the 31-game, 10-team tournament. The NBA on Monday saw its first games of the season postponed when 10 Chicago Bulls players and additional staff members were placed in health and safety protocols requiring the rescheduling of two contests. The virus has also impacted college sports, including at Tulane University in New Orleans where the men"s basketball team has been temporarily shut down due to multiple positive cases of COVID-19 within the program. The decision resulted in the cancellation of two games.