He's 22 so if he does sign it's not going to be just for a couple of years - it'd be a 5/6 year deal no doubt.
Yes he has room for improvement but the potential is there, he might not be a ready made/finished article signing but he's certainly the outstanding candidate in a pool of very few in his position.
He has Premier League, Champions League and international experience and is homegrown, also has good pedigree having come through at Chelsea.
We may take the risk in paying a larger fee now but it could prove good business down the line - even if it didn't work out with us after a few years there would still be resale value given his age and home grown status.
When you break it down rather than just looking at it face value it makes sense.