Sounds a lot like Insua too. Will be interesting to see what the reaction will be when he (inevtably) has some poor games for us.
It depends what the state of the squad is.
Look at the likes of Rafael at the Mancs and he has been eased in very gently because they have Brown, Neville, and O'Shea, he is left out when he's on a shocking run and nothing gets said.
Insua was lambasted because he made a mistake, whether it was positioning, tackling etc,. almost every match with no respite. Insua wasn't being blooded he was being sacrificed.
Johnson is the one being looked at now because he's in a very similar situation to Insua last season, he's in a team that relies on a strong defence and it turns out he can't defend. There's a place for Kelly in a side like this.