Writing in The Guardian, Dominic Fifield says that,
Essien returns to a midfield whose energy is generally supplied by the aggressive, box-to-box running of the Brazilian Ramires these days. Frank Lampard retains an eye for goal but his selection feels game-specific, with Raul Meireles a more subtle creative presence in the side and Oriol Romeu a tidy distributor rather than ferocious tackler. John Mikel Obi, currently hamstrung, is another option. Essien, even when short of games, would offer any of that quintet cover, when emerging from the bench. When fully match fit, and with bite restored, he would hope to challenge for a starting place, whether it be in the shielding role currently occupied by the young Spaniard, or as one of the more mobile options across the centre.
This scenario - where Essien can deputize for, or replace, any of Chelsea's current starters - is a nightmare for fantasy managers. From week to week we won't know how Andres Villas-Boas will line-up his midfield three, and surely when we try to guess we'll be wrong.
My guess would be that it's Romeu who is most under threat. Essien probably can't replicate Ramieres (or his own past) dynamism, but he could sit in and shore up a Chelsea side that has become a bit of a soft touch. That would mean one spot for either Lampard or Meireles. Alternatively, Romeu could keep his spot and Essien makes one-from-two into one-from-three.
Most immediately, I worry about Romeu this weekend at Norwich. I have him in my fantasy team but 1) Chelsea don't keep many clean sheets, and 2) it's now very likely that Essien comes in for the youngster on the hour robbing him (and me) of clean sheet points, if available, and point-scoring opportunities in general.
On a related note, what if Ramires becomes the right-sided attacker for Chelsea rather than a midfield option? He played there against Sunderland in Daniel Sturridge's absence, though he didn't do anything of fantasy value. If he is indeed thrust further forward, he could become a very valuable fantasy asset and maybe even clear up this midfield muddle.