Bruma is not ready for Chelsea. We all know about the high demands of being a CB for a top side. You have to deal with a lot of pressure, have to be consistent and you're not allowed to make mistakes (look at the treatment D. Luiz and Koscielny received). Bruma's talented for sure but not ready. He's doing well for HSV but still isn't good enough and most importantly, he lacks experience (crucial for a CB, how many CBs in their early 20s have a starting spot for top side? Pique was the only exception.). This is his first year he's been playing regularly at top level and at HSV he's allowed to make mistakes and plays with little pressure, compared to the pressure at Chelsea. He'll need at least two years of regular football before he's ready to play regularly at Chelsea, if he keeps improving, and by that time Terry's time as certainty in the starting line-up will be over. Look at the likes of Evans, Smalling and Jones. Evans has been in the Utd squad for a long time and he's almost 24. He's still not ready. Smalling, 22, is (very) talented but he's not ready for a starting spot either. And Jones is probably the most talented but he's been playing at RB and CM a lot more than CB as he's not of the minimum required level yet. Or what about Djourou, almost 25, at Arsenal. He was always seen as a big talent but whether he'll even make it at Arsenal is something to wonder about. The arrival of Cahill doesn't mean the end of Bruma at all. That all depends on the development of Bruma.