The Blues are in the hunt for a new left-sided defender in the January transfer window and have long held an interest in Alex Sandro.
However, Juventus are maintaining their stance of wanting to keep the Brazilian until the summer and that has prompted Chelsea to explore other options.
Chelsea have yet to make a bid for Emerson, who has only just recovered from an anterior cruciate knee ligament injury to make his first two appearances of the season, but he is thought to be valued at around £22 million by Roma.
The 23-year-old is also interesting Newcastle United, but the fee is thought to be outside their price range, while Juventus are considering him as a replacement for Alex Sandro, who has stalled on renewing his contract for many months.
Chelsea's switch to Emerson may also be due to Paris Saint-Germain's serious interest in a summer move for Alex Sandro, which could see the Premier League champions enter a bidding war with one of the world's richest clubs.
Additional reporting by Bruno Andrade