When Aleks Zinchenko went down clutching his hamstring in the 83rd minute at the Etihad on Saturday evening Manchester City were faced with finishing the game with 10 men.
The left-back received treatment by club medical staff before managing to carry on for the last 10 minutes of the game but luckily for Guardiola the defender brushed off any worries after the final whistle when he admitted it was cramp that had forced him to go down.
For a squad with so much strength in depth at the moment there is little cover at left-back. In fact playing new signing Joao Cancelo out of his favoured right-back position would appear to be the best option should Zinchenko drop out of the team due to injury.
In one of the more surprising moves of the summer transfer window the club decided to bring Angelino back to the Etihad from PSV Eindhoven. The 22-year-old had a buy-back clause that City cashed in on and was swiftly handed the No 12 shirt.
MEN Sport understands the plan is for the Spaniard to be a regular part of the first team set up this season and there are no plans to send him out on loan. Yet, the defender has missed out on the match-day squads for the first two league games of the season and had to settle for a place as an unused substitute in the Community Shield against Liverpool.
Guardiola used the pre-season tour of Asia alternating between Zinchenko and Angelino but it soon became clear who his first choice was going to be. While rustiness and perhaps nerves can be used as an excuse for his first performance against West Ham, he did little to improve over the games in Asia to suggest he is going to be fighting for a place in the starting XI this season.
Then there's Benjamin Mendy.
The Frenchman is still regaining his fitness after another long spell out injured and Guardiola has yet to see a consistent run of form from the World Cup winner.
Which then leads to City's new recruit Cancelo. "Cancelo is a little older than Rodrigo and gained lots of experience at Juventus," Guardiola wrote in his programme notes ahead of the 2-2 draw against Tottenham.
"He can play on the left as well. He's going to settle in well. When you play regularly at Juventus, an important team, you have the mentality to win, win, win. That is good for our team, too."
The City boss praised Angelino, too, in the same programme notes.
"Angelino has also come back and he has improved a lot since he left," he said. "He is still young and is an adaptable player who will get even better."
Adaptable, but, as it stands not deemed good enough to make the bench over Cancelo who has yet to play a match with his new teammates.
With question marks over Mendy's ability and how he fits in with this squad, left-back is a problem that Guardiola needs to be wary of. And while Kyle Walker may have been wary over his place in the team, it could end up being Angelino and Mendy who have more of an issue with the Portuguese international's arrival.