That does not bode well for Andre Villas-Boas' side.
Ramires has been very good this year. He has made 26 appearances for the Blues, and for the most part, he has been the most consistent midfielder for the club.
He is all over the pitch, seems to be everywhere at once, and his hustle and motor are unmatched. For a team that has had an inconsistent year, Ramires' work ethic has been a constant.
Now it's gone.
That's not good news.
The midfield is already thin. Michael Essien is slowly coming back from yet another injury, and no one can be sure how effective he will be upon his return.
Frank Lampard has a slightly torn calf, and there is no guarantee that he will be 100 percent when he returns as well. John Obi Mikel has been nursing a hamstring injury, which has clearly affected his play.
How big of an issue is Ramires' injury?
Oriol Romeu has been playing consistently in the EPL, but Villas-Boas seems reluctant to give the kid the position full time.
Raul Meireles has been good, but he's the only seemingly healthy and trustworthy midfielder left right now.
With so many things going wrong in the Chelsea midfield, they could ill afford a Ramires injury as the schedule gets busier. There are going to be multiple matches every week, and Villas-Boas does not have too many options in the midfield.
Even though it's only a month, February is incredibly important to the Blues. They hope to win some silverware, so the FA Cup and Champions League matches are imperative to their goals. They want to play in Europe next year and the Premier League games are equally important.
Essentially, every Chelsea match will have some form of significance—even more so than normal.
As a result, the Blues need all of their players to be at 100 percent, or close to it. That's not happening.
For the whole season, Ramires could be relied on. Now, that's not the case.
His consistent play and good health helped Chelsea for nearly six months, and now he must sit out a potentially season-deciding month.
At the end of the season, this stretch without Ramires could come back and haunt Chelsea.
Let's hope not.