#3 Intense competition from rivals
Manchester City's Premier League title rivals Manchester United have strengthened their back as well as attack with the additions of Raphael Varane and Jadon Sancho respectively.
Meanwhile, the 2019-20 Premier League champions Liverpool are looking to make a fresh start after reinforcing their defense.
Virgil van Dijk, runner-up for the 2019 Ballon d'Or award managed 72 minutes in the friendly against Athletic Club. Even if Liverpool decide not to risk him in the first few matches, they have enough depth in defense to cope with his absence on a short-term basis.
And who can count Chelsea out after their heroics in the Champions League last season? The 2020-21 Premier League season will be Thomas Tuchel's first full season in charge. He would have had enough time to get his ideas across over the course of a full pre-season.
Chelsea are further poised to bolster their attack with the addition of former striker Romelu Lukaku, who arrives on the back of an excellent season in Serie A.
Tottenham have also made an excellent addition in the form of Cristian Romero and remain keen to bolster their attack.
As such, there will hardly be any chance for Manchester City to put a foot wrong in the title race.
#2 Manchester City's focus on the Champions League
Manchester City went closer than ever to winning the Champions League trophy last season, only to fall just short, losing the final by the thinnest of margins.
Pep Guardiola has been at Manchester City since 2016 and the only title that has eluded him is the Champions League trophy. Guardiola has won the Premier League thrice in his five years.
The focus this season for Manchester City will naturally be on winning that competition and it could come at the expense of Premier League silverware.
During the busy months in the Premier League, Guardiola's desire to succeed in the Champions League could be a cause for concern for Manchester City.
If the Spanish tactician prioritizes the continental title, it could result in City falling off the rails during what could be a fiercely-contested Premier League title race.
#1 Pep Guardiola's fatigue as a manager
During Guardiola's managerial career, the Manchester City stint has been the longest. He started with Barcelona's B team and was given the manager's role with the senior team a year later.
He left that role four years later, adding three La Liga and two Champions League honors to his name.
Guardiola took up the manager's role at Bayern Munich a year later and stayed with them for the next three years. During his tenure he won as many as 82 of the 102 games he was in charge.
Though the Spaniard left without winning a Champions League trophy, he won three Bundesliga titles in the three years he was in charge.
While domestic leagues have never been a problem for the talismanic manager, it is the Champions League trophy that has eluded him recently. And it seems that he is only there at Manchester City for that one reason.
A fourth Premier League title in six years will obviously be something that Pep Guardiola will cherish before he moves on to his next challenge. However, it won't be a piece of cake, at least this year, given the kind of competition other teams are willing to provide.
Could Guardiola feel bogged down by the fatigue of having had to wait so long to achieve the holy grail at Manchester City?
Answers are set to unfold this season, which will be his fifth at the Premier League club.