The Blues have taken just eight points from the 15 on offer through the opening five games of their 2020-21 campaign.
That return has them sat 11th in the table, while they now face the prospect of being without their all-time leading goalscorer for the foreseeable future after seeing Aguero forced off against the Hammers.
Asked about his Argentine frontman on the back of a frustrating afternoon against the Hammers, Guardiola told BT Sport: “Injury. No, I don't know [what it is].
“It looks like a muscular injury.”
City are far from being the only title hopefuls to have suffered an inconsistent start to their domestic campaign this season, but Guardiola admits that his side have work to do after finding a winning formula elusive once again in the East End.
He said, after seeing half-time substitute Phil Foden cancel out a spectacular opener from Michail Antonio: “We started really good, we concede a goal the first time they arrive. They defend so deep and we had the chance at the end to score the goal. Now we move forward.
“I think we didn't play bad except for the last 10 minutes of the first half. They have many players arriving in the box, we had periods of that but we had the chances to score and we didn't.
“We started really well. We suffered in the last 10 or 15 minutes of the first half. In the second half we were better and scored early. We had the chances we needed to win the game, but unfortunately we couldn’t score.
“We created enough. Their defenders were defending so deep so it’s difficult to find spaces, but we had the chances.
“I’m not a guy who can predict the future. We’ve already dropped seven points, which is a lot. But we’ve struggled a lot for many reasons. We have to take things game by game and see what happens.”