FC Porto reported last Sunday that Pepe contracted a muscle injury in his right leg during their game against Portimonense the day before.
With Sergio Oliviera out for the first leg also due to suspension, I bet Chelsea would fancy their chances higher with this two ruled out of part of the tie.
The 1st leg of the Champions League match will be played immediately after this ongoing international break on April 7th.
Chelsea currently have no suspensions for the game and are expecting all their injured players to be fit by then.