We're obviously waiting to see how the situation with Toby resolves. There's no point in bringing any more CB's if there is a reasonable chance of Toby signing for us.
We most certainly have a list of possible replacements. Although, if there is no good replacement for Toby available, to me it wouldn't be a disaster to go with the players we already have, and promote Yoshida to the starting lineup. He's no Toby, but he improved a lot in three seasons for us and can do the job. Then we have Gardos as a first substitute. He also showed some promise, hell he played in wins on Emirates and Old Trafford, that's got to amount to something. And we did brought him presumably because we saw some potential in him and it wouldn't be the worst idea to place your trust in the player you already have.
And then there's Stephens/McCarthy as fourth option, they got to be introduced to the fist team sometimes.