If one of the criteria for this piece is players who won't necessarily win you the game, but you risk losing without them, then Ramires certainly comes into play.
He pops up with goals every now and then, typically after a galloping run that causes lactic acid build-up just by watching. But his value to Chelsea is similar to Park Ji-Sung's. In the big games, his athleticism sees him cast into the role of omnipresent destroyer.
At the Nou Camp in Chelsea's famous run to the Champions League trophy he was excellent - in both legs - setting up Didier Drogba for the only goal of the first, and scoring a crucial strike in the second. But with the Blues down to 10 men, it was his relentless pressing and tireless running that compensated for the numerical disadvantage.
The Brazilian was suspended for the final, and Chelsea missed his presence, and Roberto Di Matteo opted for the security offered by Ryan Bertrand in his absence.
But that selection emphasises Ramires's importance. He can do the defensive job of Bertrand, and offer the attacking threat of a Victor Moses. He can score the important goal one minute, and close down the space the next. In a team of stars including Eden Hazard, Juan Mata, Frank Lampard and John Terry, Ramires is arguably Chelsea's key cog.