As such, his eventual fee was a small one, departing the Etihad on a permanent basis for just £7.2m.
It makes his rise all the more incredible, therefore, that not even a year later he would be back in England, joining Antonio Conte in north London.
Once more, there was a loan to buy involved, with a colossal fee of £39m in the pipeline if he impresses.
Such is his whirlwind journey in the last eight months that his debut for the Lilywhites could be against none other than his former employers, with Pep Guardiola’s side travelling to the capital for what should be a superb clash.
Conte, still recovering from surgery, is unlikely to be in the dugout with Cristian Stellini instead charged with motivating the team.
One decision the pair simply have to make is the introduction of Porro. A first outing against City would be a baptism of fire but in the words of prominent Tottenham journalist Alasdair Gold, it would be “mad” to start the underperforming Emerson Royal.
It was rather remarkable that the inconsistent right-back was kept on at Spurs amid a flurry of deadline day departures that saw fellow full-backs Djed Spence head to Rennes on loan before Matt Doherty’s contract was terminated so that he could join Atletico Madrid.
In the eyes of many, both should have been ahead of Emerson but he remained the last one standing.
The Brazilian may well be granted the opportunity to prove himself once again this afternoon but if the coaching staff have any sense, it will be Porro who starts.
The man currently ahead of him in the pecking order is currently averaging a disappointing Sofascore rating of 6.87 this term and despite scoring against City a few weeks ago, has been a “liability” in the eyes of many this season, particularly outspoken pundit Jamie O’Hara.
Therefore, the addition of Porro to this team could be truly game-changing, with the “special” 23-year-old – as dubbed by Zach Lowy – possessing all sorts of exciting tools.
Indeed, transfer insider Dean Jones told Football FanCast this week that he could “transform” the club and judging by the way Emerson has played, it’s not hard to see why.
The Spaniard has been seriously impressive this term, scoring twice and laying on six assists for his teammates as a marker of his attacking qualities in Portugal.
Defensively Porro has also been astute, making 1.4 tackles per match domestically, while making 2.8 in the Champions League. Comparatively, Spurs’ current option in that third of the pitch has made 1.8 in Europe’s premier competition and two in the league, an indication of just how inconsistent he can be.
As such, it is finally time for those behind the scenes at Tottenham to oust the former Barcelona talent; it is Porro they must put their faith in instead.