I don't think we need to be signing any CB this window. Our goals against was very good last season and any deficiencies we had were more due to a sheet MF then CBs. Other than the fact that we have more pressing needs, my biggest issue bringing in a CB is that it leads many journos to the conclusion that Arteta may not give Saliba a legit chance. Mavro was never gonna stay. Arteta doesn't rate him and the fact that we are only getting 7m is an indication that he isn't rated terribly highly by anyone with money to spend.
If they are spending that kind of money he will most certainly be brought in to start. And given our fixtures next season we only need 3 1st team CBs, 4 absolute max. That means someone has to move to maintain a balance in numbers.
- Gabi isn't going anywhere. He is an Arteta signing and only 23.
- Holding is arguably our best remaining CB but buying White directly replaces him in the starting spot. He was almost sent out on loan last summer and was only kept around due to injuries. Even then, Arteta only seemed to play him when he had to, often choosing Mustafi or Luiz instead.
- Mari is the oldest of the group and probably the best pure defender but is slow and not a great ball progressor. He is also VERY left sided.
- Saliba is young, will be HG and is coming off of 1 full and 1 half season in Ligue 1 where he was named one of the leagues best defenders. Arteta seems to have something against playing him. Not been openly critical but it is very similar to his refusal to play other young players (ESR, Martinelli, AMN, Nelson) until there was no other option. While they aren't left footed, both Holding & Saliba are very capable of playing the left. Saliba actually played 90+% of his Nice games as LCB and while he is prone to youth mistakes he pocketed several quality ST (Mbappe) last season and is just as good a passer as Luiz.
For me Mari makes the most sense to move if you only move 1 but I am not opposed to the idea of moving 2 as was suggested from the other board above. I like Holding but A) I don't know that Arteta really rates him, B) he is likely the worst passer of the bunch and C) though he is only 25 I question whether he will ever really get much better.