The end of the 1917-18 season also saw the end of the Montreal National Hockey Club. The Nats, having gone a flat 0-12 in the second half, stated that they were deactivating their franchise, just as Quebec had done the year before. This left just three clubs - the Valiants, Athletics and the Dukes. The latter club, the newest member of the NAHC, was also the one drawing the most attention in newspapers throughout the 1918 offseason.

This was largely because Jack Connolly, the former owner of the Toronto Silver Skates, was suing the NAHC after his abrupt dismissal and replacement by Bert Thomas and his Toronto Dukes, whose roster bore a more than passing similarity to the Silver Skates. Connolly's megalomania, ruthlessness and single-mindedness would not permit him to go quietly. Connolly's suit sought the return of "his club" or, barring that, a significant sum of money from Thomas for his "illegal seizure" of the club. A second suit challenged the NAHC's by-law by which he had been expelled from the organization. When in the summer of 1918 the courts failed to decide in his favor on either suit, the silver magnate turned his gaze southwards - to the thus-far untapped markets in the United States. It was there that Connolly would make his next mark on professional hockey.

The TCHA also saw some change in the 1918 offseason. The Victoria club would return to action, with their arena once again available with the November armistice ending the Canadian Army's need to use it for training purposes. But the TCHA lost a club as well - the Seattle Emeralds folded due to significant financial issues. With the U.S. having entered the war, the public in Seattle didn't support the club as well as they had in years prior and the owners also weren't fiscally responsible, leaving the club's budget on "thin ice" throughout the season. With none of the independent business success of the Yeadon family or the owners of the Portland club, the Seattle group disbanded. So the TCHA, like the NAHC, would be a three-team circuit in 1918-19.

As the autumn wore on, the First World War finally came to an end with an armistice ending the fighting on November 11. That was too late for the many hockey players in military uniform to be discharged and returned from France in time for the season openers in either the TCHA or NAHC, but there was at long last some light at the end of the tunnel. Unfortunately for the world at large, that light was being dimmed by a new and far more insidious problem - the so-called "Spanish" Influenza that appeared in the fall of 1918 and spread rapidly around the world, coming to North America on the troop ships carrying soldiers back home. 

Pro hockey's first (but by no means last) victim of the Influenza pandemic was Ottawa forward Jacques Tremblay. The 32-year-old had been with the Athletics since their 1909 debut on the professional scene. While never one of the game's biggest stars, Tremblay was a solid, hard-working - and hard-hitting - player. He also had a day job working for the Interior Department in Ottawa (most hockey players had "day jobs" to supplement their small salaries from hockey). When his wife fell ill in the early fall, Tremblay cared for her at their Ottawa home. He soon contracted the flu himself and on October 10, 1918, he passed away from pneumonia caused by the flu, one of the millions of people worldwide who would lose their lives to the illness. In nine NAHC seasons, Tremblay scored 64 goals and 26 assists in 164 games. He also racked up 531 career penalty minutes as the main tough guy on the Athletics roster.

Both pro leagues would play a regular, non-split season in 1918-19. The NAHC would play an 18-game slate while the TCHA would opt for 20 games. The leagues had distinct identities now - the western loop was finesse and offense-oriented with forward passing, striped zones and the rover position among its rules. The NAHC had none of these and was known as a hard-hitting, defense-oriented circuit - and instituted a rule change of its own for 1918-19 that would change the game as it allowed goalies to leave their feet to stop a shot, something that had previously always been illegal. The impact of this change would be both significant and immediately impactful.