There were rumours Rudan may activate a clause in his contract which would see him depart the club after just one year of his two-year contract.
Against this backdrop, the Phoenix faltered in February, picking up just 2 points from a possible 12.
On the 7th of March, Mark Rudan joined Jason Pine on Radio Sport studio to address the speculation, assuring fans and stakeholders that he was committed to the role, despite admitting he was in the process of making a decision.
Back on the field, the Phoenix embarked on a magnificent March. Fifteen goals in three games and the Nix were up to fourth.
But the rumours about Rudan continued to swirl, and were added to by fresh speculation that not only would he be leaving the Phoenix, he'd also been appointed coach of the A-League's newest expansion franchise Western United, based in Melbourne.
Fan opinion quickly began to split on Rudan.
He'd transformed the club, but it now looked inevitable that he wouldn't be seeing out his two-year contract, and would be joining a new A-League rival.
The players looked distracted, and the team lost consecutive games in Adelaide and Brisbane.
Three days after the second of those defeats, on Monday April 15, the club announced Rudan would be leaving at the end of the season.
The news came as no surprise to anyone really but for some it felt like salt in the wound, as he had taken the club to an extraordinary position, only to leave at its apex.
Two days later, Rudan fronted the media himself to explain the reasons for his departure. This was a very different Mark Rudan to the bullish, exuberant, confident character who had faced the cameras and microphones in the very same room when he was unveiled as Wellington coach in May of 2018.
Instead, it was an apologetic, softly-spoken, repeatedly contrite Rudan who said the word "sorry" at least a dozen times during an at times emotional media conference.
There was a significant amount of gratitude for the way he'd turned around the flailing fortunes of a struggling football club, but many also feel let-down by his decision to leave the job midway through his contract.
Rudan also claimed he hadn't signed a contract to coach anywhere else, and any announcement on his next move wouldn't come until the Phoenix had played their final game of 2018/19.
The Nix had already confirmed their playoff spot before their final home game of the regular season against Melbourne City which was locked at at 2-all in added time.
Roy Krishna pushed home his 18th goal of an absolutely outstanding season which won him the competition's Golden Boot and also saw him awarded the Johnny Warren Medal for the A-League's player of the season. The Nix made the playoffs for the first time since 2014-15, completing a remarkable turnaround with Rudan at the helm.
Unfortunately they were to fall at the first playoff hurdle - away to Melbourne Victory. The very next day, the 4th of May, Sydney FC assistant coach Ufuk Talay was announced as Rudan's replacement as Phoenix head coach.
But there was more drama to come.
Filip Kurto, who'd won the competition's best goalkeeper award announced he was leaving the Nix to join Western United.
Two days later, livewire midfielder Max Burgess followed suit.
It wasn't until a week after that, that the worst kept secret in the A-League was confirmed - Mark Rudan wasn't going back to Sydney at all, he was instead headed to Melbourne to coach Western United.
That left a very sour taste in the mouths of many Phoenix fans who felt Rudan was recruiting players for his new club while he was still in charge at Wellington.
That talk only intensified when club skipper Andrew Durante, the veteran of 11 years in Wellington, also announced he'd be leaving to join Rudan at Western United.
There were other key departures as well.
After a long period of deliberation Krishna, who had become the club's all time leading goalscorer during the season, announced he'd signed with Indian Super League club ATK, and would be joined by strike partner David Williams.
In early July, young Kiwi star Sarpreet Singh took up a dream deal with German super club Bayern Munich.
Others to leave included imports Mandi, Michal Kopczynski and Cillian Sheridan, defenders Tom Doyle and Dylan Fox and striker Nathan Burns.
When Ufuk Talay arrived at the club to take up his new role as head coach, there were just seven players on his roster.
As luck would have it, the first game of the new A-League season in October would see the return of Rudan, Durante, Kurto and Burgess to Wellington, this time in Western United colours.
Rudan was bombarded with constant boos from the Phoenix's Yellow Fever faithful, but he was to have the last laugh - his side winning 1-0.
Top 15 sporting moments of 2019
No 15 - Eliud Kipchoge's sub-two hour marathon
No 14 - The Rise of Bianca Andreescu
No 13 - Courtney Duncan becomes MX World Champion
No 12 - The Ashes