The Blues were after a new centre-back throughout the summer, but saw their efforts to sign Everton's John Stones and Paris Saint-Germain's Marquinhos turned down.
Jose Mourinho made three formal offers for Stones, with the highest bid reaching around £35 million, and also made two formal bids for Marquinhos on Transfer Deadline Day.
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Despite the concrete interest in the two centre-backs, though, Mourinho failed to capture either of them and eventually made two last-ditch additions to his squad.
Papy Djilobodji was brought in from Nantes, whilst Michael Hector soon followed from Championship side Reading - both seen by many as panic buys.
With the two Deadline Day signings not in Mourinho's first-team plans, Chelsea's back-line has largely stayed the same from last season, with the exception that Kurt Zouma is gradually worming his way into the side ahead of veteran and captain John Terry.
However, full-back Branislav Ivanovic is enduring a nightmare run of form, with the champions leaking goals on a regular basis - changes are indeed needed at Stamford Bridge.
As a result, Mourinho appears to be growing tired of defensive lapses and is ready to shake things up in January, with Manolas top of his wishlist.
The Greek international was a target for Premier League rivals Arsenal before he swapped Olympiacos for Roma in 2014, and it looks like he's attracting interest from England once again.
It's not yet understood how much Chelsea are prepared to offer Roma for the 24-year-old, but it's believed a formal offer will be launched in January.