But Aguero returned to training on Monday and is in contention to face the Baggies.

"Today he was training but in the last two or three days he could not train so we will decide tomorrow," Guardiola said.

City have been a long way from their free-scoring best at several points this season, hampered by injuries that have hit both Aguero and fellow striker Gabriel Jesus.

But they have made significant progress at the other end of the pitch, with Saturday making it six straight games in which Guardiola's side have kept a clean sheet.

John Stones, whose City career had appeared over at times last season, has returned to play a major role – starting four of those games and playing over an hour as a substitute in the 3-0 Champions League win over Marseille.

That has meant a limited role lately for Aymeric Laporte, now without a Premier League start since November 21, but Guardiola said he would need all of his defenders in the weeks ahead.

"It depends on performances and John is performing well, that is why he is playing," Guardiola said.

"But there are a lot of games and everyone has to be ready. Maybe they are not playing much but around the corner they may have a chance and they have to be ready."

Saturday's draw at Old Trafford kept City down in ninth place in the congested top half of the Premier League table, still four points adrift of the top four but with a game in hand on most of those above them.

Both City and United have been playing catch-up all season having started their campaigns late due to Champions League commitments in August.

The intense fixture list has hardly helped as they find themselves trailing several sides who are not playing in Europe, with Southampton, West Ham, and Everton all making strong starts.

But Guardiola believes the break from European football, combined with the busy festive period, will help level the playing field in the league.

"So far the European teams have played in different conditions to everyone else," he said. "Now everyone will play the same amount until February.

"We are lucky to be playing in Europe but now is the moment to play another game and try to beat them."