Beyond where he fits on the pitch, Willian presents a different dilemma for Chelsea. Assuming he's granted a work permit to play in England, the Brazilian will occupy an international roster slot for the Blues 25-man squad to be submitted at the close of the window. In and of itself, that is not an issue, as Chelsea have only filled 16 of the 17 available slots.
Where this becomes interesting, however, is when we look at the striker that Jose Mourinho still hopes to sign. If Wayne Rooney comes aboard, his homegrown status assures that this isn't much of an issue. If Chelsea have to move on to plan B though, there's suddenly a potential roster crunch*. Someone would have to be removed from the roster in order to make room for a striker requiring an international slot.
*Assuming the plan isn't a homegrown striker such as Darren Bent or Jermain Defoe
The speculation making the rounds this morning is that Victor Moses will likely be the odd man out, and will be heading away on loan. That doesn't help at all with the roster situation though, as Moses is the only attacker Chelsea have that currently counts as homegrown.
Should Chelsea add a striker that doesn't count as homegrown, the obvious choice to cut from the squad seems to be Henrique Hilario. Jamal Blackman can handle the role of third choice without much issue, and Hilario can hang out and tutor the youngster while still collecting his check.
The other feasible alternative would be to ship out Demba Ba just six months after signing him from Newcastle. The Senegalese striker has been mostly disappointing since joining the Blues, and wouldn't seem too likely to get a ton of minutes if Chelsea were to add to the depth at his position. I'd add Fernando Torres to the mix, but the simple truth is that his wage makes him nearly impossible to sell. At this point, I'd almost hope our center forward addition ends up being Wayne Rooney just because his homegrown status would help down the line.
Regardless, the surprise move for Willian has pretty much assured that Chelsea will be an interesting team to watch as the transfer deadline approaches. We're now looking at an obvious surplus in some areas, and might need to unload in others in order to fit everyone in. The next week should be fun, shouldn't it?