If he joins this season we can send Masche packing. He's already lost his spot as a starter and will likely lose his spot as 3rd CB very quickly with the way Marlon has played.
I think you are too quick giving up on Masche. Marlon has played a few good games for first team but he's still not proven against top competitions. I wouldn't be comfortable having inexperienced at top level (Marlon) and not adapted to our system (Mina) backups if whatever happens to Pique or Umtiti. It's just too much of a risk to change half of CB line in one summer and I'd prefer both Marlon and Mina adapting to our first team with less pressure. If one or both of them could do "a Umtiti" then great but nobody should expect and demand they will adapt and start to play regularly on high level as quickly as Umtiti did. That's why I'd keep Masche for another season and if in the end we sign Mina already this summer then either him or Marlon should go on loan for a season.
Another thing: I know I'm repeating myself but we can't have both Marlon and Mina next season because we currently only have one free non-EU spot. Neymar could get his spanish passport soon but this is Spain and it's summer so it could also take time. Until he officially gets a passport it wouldn't be smart to plan selling Masche as in the end we possibly couldn't register one of Marlon or Mina. I really wouldn't like us to get into a situation where we'd have to panic buy in last days of August or possibly keep Vermaelen (and hope he'd stay healthy for more than 2 games
) if that scenario happens.
Also, not to mention that we might also go after Coutinho (if we won't get Verratti or Dembele) later in summer and we'd also need non EU spot for him.
