The Frenchman was forced off at the Bernabeu with a hamstring injury midway through the first half.
It was another frustrating setback for the 25-year old after his return to action following a long-term knee injury.
Speaking at his pre-match press conference ahead of Sunday’s Carabao Cup final against Aston Villa, Pep revealed that he was hoping Laporte could be fit to return towards the end of March.
“He has a hamstring injury, it should be three weeks or a month - more or less,” said Guardiola.
Now, a defense will continue in flux and more disarray is expected. City of course head in to a heavy schedule with a final Sunday, the second leg of Champions League and many Premier League games.
Pep will have his work cut out for him as he prepares his squad with a missing lynchpin in Laporte.
Time will tell how the squad responds.